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Mirroring Controllers - What have been Your Experiences?
Posted by
Cliff
on Thu Aug 28, 2003 05:42 PM
from the that-fuzzy-SCSI-feeling dept.
from the that-fuzzy-SCSI-feeling dept.
Today's installment is a lengthy (but hopefully informative) piece on mirroring controllers. Ever had weird problems with a FastTrack TX2000? Are you curious how well HighPoints RocketRAID boards are really supported? Ever wondered which controller gives you the best performance for every dollar spent? In true Slashdot tradition, we're taking the issue and throwing it out to you, the readers. Futurepower(R) is willing to start us off with a wealth of information on his experiences, and I'm hoping a few of you are willing to do the same.
Futurepower(R) asks: "What experiences, both good and bad, have you had with mirroring controllers? Are there manufacturers I haven't found?
For those who are interested but don't have experience, mirroring controllers (RAID 1) provide several advantages:
ECS (EliteGroup) has made 11 motherboards with on-board RAID mirroring controllers. One of them, the P4VXAD, has a Promise controller and costs about $52. What's that about? Employees at Fry's tell me that ECS has the poorest quality control of any of the motherboard manufacturers that they sell. To me, ECS motherboards seem to have surprisingly high quality. However, we have only tested three, and only one extensively.
Silicon Image makes, or made, their 0680 RAID chipset, and Koutech Systems sells the IOFLEX-Pir133 using that chipset. It costs $25 retail. I tried a Koutech card and had a lot of trouble with it, even after updating the BIOS. I talked to an application engineer at Silicon Image and a manager there. I was told that SI bought the technology from another company, and apparently it is no longer supported, doesn't work well, and the company does not intend to put more money into it. I found that the Koutech card corrupts files. The card gives a Stop 07B error when going into the Windows XP Recovery Console, unless the driver is loaded by hand, every time. I lost a lot of time with a product that apparently should not be sold.
My experience with mirroring controllers is mostly with those from Promise Technology. I've been using Promise mirroring controllers since they began making them.
The good about Promise:
The Acard controller supports SuSE, Red Hat, Caldera, and Turbo Linux, it says. But remember, Froogle found only one vendor.
HighPoint says they support Linux: "Linux Red Hat 7.3 & 8.0 (Software RAID Only)". This apparently means the card does not support Linux at all, since Linux has software RAID built in.
So, that's the extent of my knowledge and experience. Can you provide further insight?"
For those who are interested but don't have experience, mirroring controllers (RAID 1) provide several advantages:
- They prevent data loss when a hard drive fails. The other drive in the mirror takes over seamlessly.
- Reading of data is considerably faster since the controller reads the data from the drive that has a head closest to the data.
- You always have a full hard disk backup that you can pull from your system at any time, such as before installing new software.
- You can clone a Windows XP drive using the RAID card, and you will have a bootable copy. This is valuable, since the Windows XP file system cannot copy all of its own files. (Don't flame this; it has been verified many times by Microsoft employees, who often suggest using the third-party tools.)
- Promise Technology's FastTrak TX2000 is available for about $85 delivered.
- HighPoint's RocketRAID 133 costs about $80.
- ACARD Technology's AEC-6880 costs about about $85. Froogle found only one vendor. That's scary.
- Adaptec makes the ATA RAID 1200A, which is available for about $59 before delivery charges.
ECS (EliteGroup) has made 11 motherboards with on-board RAID mirroring controllers. One of them, the P4VXAD, has a Promise controller and costs about $52. What's that about? Employees at Fry's tell me that ECS has the poorest quality control of any of the motherboard manufacturers that they sell. To me, ECS motherboards seem to have surprisingly high quality. However, we have only tested three, and only one extensively.
Silicon Image makes, or made, their 0680 RAID chipset, and Koutech Systems sells the IOFLEX-Pir133 using that chipset. It costs $25 retail. I tried a Koutech card and had a lot of trouble with it, even after updating the BIOS. I talked to an application engineer at Silicon Image and a manager there. I was told that SI bought the technology from another company, and apparently it is no longer supported, doesn't work well, and the company does not intend to put more money into it. I found that the Koutech card corrupts files. The card gives a Stop 07B error when going into the Windows XP Recovery Console, unless the driver is loaded by hand, every time. I lost a lot of time with a product that apparently should not be sold.
My experience with mirroring controllers is mostly with those from Promise Technology. I've been using Promise mirroring controllers since they began making them.
The good about Promise:
- Promise has been selling RAID 1 controllers a long time. They work.
- Promise controllers can clone a hard drive quickly.
- Now some motherboards have Promise mirroring chipsets. You can get the entire motherboard with the Promise controller on the board, for maybe $50 more than the Promise controller card alone.
- Linux drivers are available. The web site says, "Windows XP/2000/NT4/Me/9x; Novell NetWare 4.1x/5.x; RedHat Linux 7.0/7.1/7.2; TurboLinux Server 6.5; TurboLinux Workstation 7; SuSE Linux 7.2; OpenLinux 3.1" Does that mean that later versions of Linux can't use this card, or did Promise forget to update the brochure PDF file?
- Promise controllers work fine under DOS, but there is no error reporting if for some reason the mirror breaks.
- Promise mirroring controllers have a software feature called "sychronization". I've asked many times over the years why it is necessary, since mirrored hard drives should be synchronized 100% of the time. I've never gotten an answer. Recently I've been told by Promise technical support people not to use synchronization, since it has caused problems. It sounds like some technical problem is being hidden.
- Promise does not support their oldest mirroring controllers under Windows XP. This is a problem since there are many business computers that are used for data entry. A Pentium II is as fast as is necessary. Windows 98 is stable with only one program running. Now those computers need to be converted to Windows XP, since Microsoft has declared that its operating systems have a curious quality: They die. (According to Microsoft, it doesn't matter that at least 100,000,000 people are using Windows 98 worldwide, it came to the end of its life on "30-Jun-2003".)
So, it is necessary to buy another controller for old data entry systems. Notice that Microsoft and Promise could decide to play this game again, and I would like to avoid the second round of buying and installing even another controller. I'd like to find a company that continues to support its products.
The speed of computers used for data entry does not matter, but the security of the data does. Hard drive failures are becoming rare, but a hard drive failure can cause a lot of problems on a data entry computer, so mirroring is required. - Some Promise controllers, especially those on motherboards, take a long time to boot. Dots crawl across the screen even if no drives are connected to the controller. Is keeping the Promise name on the screen a time-wasting sales message from Promise? Recently Promise released a BIOS upgrade for some of its cards that reduced the dot-crawling time. However, there is apparently no upgrade for Promise controllers on motherboards.
- About 2 months after I reported problems, Executive Software said they found a bug in their Diskeeper defragmentation software that might cause data corruption when used with Promise controllers. They said everyone using Diskeeper should upgrade to the new, free, minor version. I've seen no problems since then.
- Promise Technology's sales literature can be disgusting. This is the second sentence in Promise's description of the FastTrak TX2000: "The FastTrak TX2000 ATA RAID card supports Ultra ATA/133 drives to rock workstations and boost small (or large) office servers like never before." To me, this is obviously written by someone who knows nothing about the product and doesn't care.
- I find the abundant use of PDF files and unnecessary JavaScript on Promise Technology's web site annoying.
The Acard controller supports SuSE, Red Hat, Caldera, and Turbo Linux, it says. But remember, Froogle found only one vendor.
HighPoint says they support Linux: "Linux Red Hat 7.3 & 8.0 (Software RAID Only)". This apparently means the card does not support Linux at all, since Linux has software RAID built in.
So, that's the extent of my knowledge and experience. Can you provide further insight?"
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Not a first post post (Score:5, Funny)
Re:Not a first post post (Score:5, Funny)
Parent
Re:Not a first post post (Score:3, Insightful)
3ware (Score:5, Informative)
That's all I'm sayin...
Re:3ware (Score:5, Informative)
Parent
Re:3ware (Score:3, Informative)
I tried out an Adaptec 1210SA raid controller since the box claimed Linux compatability. Bull. They support a handful of distros and and even smaller number of patchlevels of kernels with their set of bi
Re:3ware (Score:3, Insightful)
The 3ware series OTOH are excellent. Good support - no download required. Web admin and monitoring available. ++
Re:3ware (Score:3, Informative)
3ware drivers have been integrated into the Linux kernel for some time. Promise, Highpoint, etc. has binary drivers that limit your kernel options.
3ware has on-board logic to han
Escalade 7500-4 (Score:3, Informative)
Re:3ware (Score:2, Redundant)
Re:3ware (Score:3, Informative)
Your also asking about adding a drive to a RAID array. Some drive arrays will allow this, but generally speaking it won't. If you want to add a drive to an
Re:3ware (Score:3, Informative)
Yes. Which is why 3ware doesn't let you do that. One drive per channel is the rule. The boards even come with single-drive ribbon cables.
Re:3ware (Score:3, Informative)
(Apologies for responding in two separate posts)
In my experience, you can plug one half of a 3ware RAID-1 mirrored set into a standard IDE controller and read the data just fine. Accessing any other levels, such as 0 or 5, would be a crapshoot on anything but another 3ware.
Re:3ware (Score:3, Informative)
In my experience, no. The Mylex raids we used "borrowed" a small amount of disk at the start of the drive for its own purposes. I would think it very unlikely that t
missing option (Score:5, Informative)
They do more than just mirroring, and aren't cheap, but if you wants the quality, you gots ta pay the piper.
Drivers are in the Linux kernel, and have been for some time. ATA or S-ATA versions available.
3Ware (Score:5, Interesting)
On the other end of the spectrum, however, is OS-level mirroring. I have only experience with Linux RAID-1, both that has never failed me either. I have run software RAID-1 for many years and have only (long ago) had problems where I had to "raidhotadd" a drive from a mirror set that was no longer recognized.
My recommendation, based on both performance and ease of use, is to use a 3ware controller. That coupled with Linux LVM makes disk management and resiliency a breeze.
My only disappointment with the 3ware controller is that one cannot make take a single disk with data on it, add a second disk and tell the controller to mirror the first disk to the second. With the 3ware, you will lose the data on both disks when making a mirror. (So says 3ware tech support.)
Parent
Re:3Ware controllers are expensive. No copying? (Score:4, Interesting)
That said, any 3ware controller can read a disk that was written to by another controller (the format hasn't changed), provided the physical interface is the same. I've used drives from a 6400 on a 7500 without any trouble.
The benefits of the special format basically amount to being able to identify what part of the array a drive is from, and it's function, while swapping them around. You can plug disk 3 into disk 2's connector, and the card will identify and deal with the situation appropriately. Pretty useful in a larger array, or if you use the same hotswap cartridges on multiple systems, and get them mixed up.
Parent
Promise TX2000 experiences (Score:5, Informative)
We use 'em at work. On the Windows 2000 side, they come with decent management software and for the most part, are relatively reliable.
However, they are far from perfect. I've had several W2K servers blue screen when doing a hot-swap. Joy.
The FreeBSD drivers are bloody stable as hell. No complaints.
The Linux drivers provided by Promise are, IMHO, a POS. Pain to compile. No management software. Diagnositics are limited. As a result, I'd go with a different IDE controller card if you want it for Linux. YMMV.
Re:Promise TX2000 experiences (Score:4, Informative)
Eventually, we started using Promise and Adaptec RAID controllers. Both have been wonderful. They both gave good warnings when one of the drives failed. We only had one problem in several years. One of the Promise controllers died of heat exhaustion, but that was the time the power supply fan went.
Parent
3ware (Score:4, Insightful)
Easily beats most if not all of these cards, especially since it is a hardware card, unlike some of those software cards mentioned.
Promise FastTrak (Score:4, Informative)
I have switched every Promise installation to 3ware cards because of this. They are open source drivers, very current, and perform well. Their tools run as a web daemon under Linux so you can check status/reconfig on the fly. Really amazing Linux support, and a reasonable price... (and no, I'm not affiliated...:) )
Re:Promise FastTrak (Score:5, Informative)
I'm writing this on a Debian Sid system with a 2.4.20 kernel, that I installed to RAID 1 on a Promise 20265 (onboard chip). To get the support into your kernel, you need:
CONFIG_EXPERIMENTAL=y
from code maturity options, and:
CONFIG_BLK_DEV_ATARAID=y
CONFIG_BLK_DEV_ATARAI
from IDE chipset support/bugfixes.
If you have a Highpoint or SII, use:
CONFIG_BLK_DEV_ATARAID_HPT=y
CONFIG_BLK_DEV_AT
Note that the following should not be set. If they are, you will not get the ATARAID functionality, and the Promise will be seen as just an ordinary IDE controller:
CONFIG_BLK_DEV_PDC202XX_OLD
CONFIG_BLK_DEV_PDC
A Debian install CD that supports Promise chips in RAID mode is out there, it's what I used to install this system. I don't remember where I got it, but Google can help. The kernel is 2.4.20, and it also supports Reiser and devfs.
Parent
mylex (Score:3, Informative)
Don't forget heat (Score:2, Interesting)
I've used the Adaptec card before, and I learned the hard way that you need to be aware of heat. Two modern high-speed IDE drives generate a large amount of heat, and if you mount the two directly next to one another in the case you may well burn one out, as I did.
The dead drive may have had some other defect, but I doubt it as the thermal alarm on the MB would sound after a few hours of usage. Even after replacing the drive (and being sure the two drives were mounted far enough apart to allow airflow
cheap cards==software (Score:3, Interesting)
get a real card or you might just as well use software raid, the good models don't come with 64mb of mem just for kicks either, and the good models have linux support too (adaptec 2400a, if that was the model i installed once, i think it is, even came with managing software that was a bootable linux cd). sure it's expensive but it's REAL, not just an ata interface and programs.
Controller Reliability (Score:4, Informative)
The purpose of a raid card is improved reliability. Thus, you shouldn't try to cut corners on quality control to save a few bucks. After all, you're already springing for two drives.
I have had very pleasant experiences with 3ware [3ware.com] controllers, both under linux and Win32. Currently I have a 6400 running under Suse 7.3, and three 7400s running under RedHat 8. With some hotswap drive bays, you can even unplug a drive with the system running.
They might cost a little more, but they're widely used under more grueling conditions than the more dirt cheap designs. Also, if you're simply doing raid 1, you can use one of their previous generation cards with no performance penalty, and save a bunch of bucks.
Not really "hardware" (Score:2)
They are a garden-variety IDE controller with some extra BIOS and driver code. They are charging you extra because you are willing to pay a premium for it.
Unfortunately, Windows XP and Windows 2000 workstation both ship with the mirroring code disabled, which is unfortunate.
Having said that, there's very little benefit in worying about if the extra BIOS and driver code is going to work under Linux. As long as the chip lets you get to the d
Re:Not really "hardware" (Score:3, Informative)
NT Workstation, 2k Pro, and XP Pro all support dynamic disks but *not* fault tolerance (defined as RAID 1 or RAID 5). They do support RAID 0, however.
The disk management interface *can* create a fault tollerant set from a workstation OS on a remote machine running NT server, 2K server, etc. That's why it's in the help file.
You can hack the dynamic disk stuff to make it think it's running a server OS (same executable i
why stop at RAID 1 (Score:2)
In addition, it seems like disks are no longer the weakest link in the MTBF chain - assuming redundant PSUs, your main concern is really your CPU/RAM/bus/chipset. To improve this situation, you need n+1 redundancy, and that in most cases means a specialized piece of hardware (h.a. NAS) or a SAN that can be failed over.
If you like that minty-fresh open so
3ware raid controllers (Score:2, Informative)
http://www.3ware.com/products/parallel_ata.a
I believe it's hardware based, so it will cost a little more than a cheaper software based card(like twice as much-- around $120). I don't have the experience with a drive failing, but setting it up was painless. All you have to do is like press a key during boottime and it's like partitioning a harddrive, but easier.
I recommend 3ware (Score:3, Informative)
I went with HighPoint... (Score:3, Informative)
Specifically, the RocketRaid 133 [highpoint-tech.com] (based on the HPT372A chipset). The card runs quite well under Linux. The Linux driver [highpoint-tech.com] from HighPoint is quite good (sadly, only partially open source) and provides a /proc interface. (Don't worry, it compiles just fine in any kernel.) Sadly, I cannot show you output from the interface because Slashdot refuses to let me post it (citing junk characters). Stupid Taco. The interface also allows you to issue commands to the controller without rebooting, but documentation is poor. The BIOS utility is also quite good.
Anyway, the device hosts two RAID-1 arrays, one with 2 80Gb Seagates (ST380021A) and the other with 2 200Gb Maxtors (6Y200P0). They appear as SCSI devices. I have tested the mirroring and I am mostly satisfied.
Basically, I simulated a failure on one disk (removing it then performing some work on the other). When I reattached the drive, the card recognized the "failure" immediately and wanted to build the array. For my first test, I let the BIOS do exactly that. Took a very long time, but the mirror was recreated successfully and there were no problems (I tested by removing the first disk and trying again--the mirror was good). The second test was letting the driver do it after the machine had booted. This was a dismal failure. The card does NOT like rebuilding the mirror once the system is running.
Performance is quite good. Even though this is not HighPoint's latest offering, I am still quite impressed. I don't have any hard benchmarks, but I can post some later if you'd like.
These two arrays are accessed by many machines in my home network over NFS and by on average 5 users logged in remotely. They serve games, web pages, and my software, movie, and music archive. These arrays take a decent amount of stress, but nothing severe.
I'll post more in this thread if I think of anything. I'll answer any questions about the card's performance if you have any.
ECS Motherboards (Score:3, Informative)
I've been nothing but plesantly surprised by the ECS K7S5A/Athlon XP combo, because:
1. SiS used to suck as a chipset manufacturer, and
2. ECS used to have REALLY bad quality control.
The surprise? SiS has one of the most stable chipsets anywhere (not the best performing, but performance is irrelevant if the drivers are wonky). Add to that the fact that I've worked with about 10 boards (all bought at different times), and I've yet to have a single problem with them under Linux or Windows (in fact, the SiS chipset seems to perform better under kernel 2.4.x with the SiS chipset than even Via). I've standardized on that combo at home and with the boards I've replaced at work.
Summary: ECS has come a long way, and SiS even farther in the last couple of years. What the boards lack in performance, they more than make up for in stability.
Geez. I never thought I'd be an SiS advocate on
Re:ECS Motherboards (Score:3, Informative)
A different friend bought an Athlon XP 1800+ and K7S5A Revision (4 or 5, don't remember which)
If data integrity is important, pony up some $ (Score:4, Insightful)
RAID experiences (Score:5, Informative)
I've used several different external RAID5 solutions, including the Promise TX8000 and Radion arrays (and a bunch of no-name brands too). Those all worked beautifully, and survived failures without any significant problems.
I've worked with four internal hardware raid solutions. Two were the Adaptec AA-130 cards years ago, and the most recent two were Promise SuperTrak SX6000. One belonged to a friend, and one went in my machine.
My friend had several problems with his. I'll leave his story at that.
I put together a nice dual processor machine for a large photo archive site. It needed lots of space, which is why we needed the RAID5. It also needed to take up as little space as possible, so we opted for putting 6 drives in a 2u case with the SX6000. The card was incompatable with the newer chipset of the motherboard. It took two weeks of daily calls to tech support before we gave up. A week later, they released a firmware update which addressed this problem. The SX6000 doesn't handle heavy read or read/write traffic very well. When we made it an active web site, the server would crash very frequently with errors about the array. If we kept the traffic slow, it worked fine, but that what we wanted from this machine. This array solution proved to be non-functional for us, so we made the machine a backup machine, so now we have like 600Gb of storage space to back servers up to.
I've heard a lot of good things about 3ware, but haven't tried one myself yet.
I've been experementing with Linux's software RAID's. I've used RAID1 and RAID5, and they both work great. I've had a drive fail on two so far, but for the number of drives we use, that's acceptable. They rebuilt fine sticking in a new drive, with very little performance hit. I do like that Linux gives decent statistics in
You seem to want multiple platforms, so I guess Linux software RAID isn't much of a solution for you.
I can simply warn against the Promise SX6000. It should have been a good card, with Promise's reputation, but I was severly disappointed.
Re:RAID experiences (Score:3, Informative)
Firstly - the Adaptec appears to simply be a third party controller with a different PCI identifier. How do we know - well if you add the adaptec pci idents to the siimage driver - it works.
Pretty much all of the controllers out there are software raid and use BIOS/driver glue to implement raid. Several vendors ship the same hardware with different drivers to sell you a variety of priced cards according to pure s/w features.
For standard PATA the Linux kernel uses its own md layer plus some
Re:RAID experiences (Score:3, Informative)
More Information: (Score:4, Interesting)
Added Information:
I wrote the Slashdot story. I've gotten additional information since then:
First, I don't see any evidence of low quality in ECS motherboards. Both ECS and Fry's employees say that the high rate of returns is due to the fact that the low cost attracts people who are very inexperienced at building computers. That seems right to me. An ECS sales representative mentions that Fry's uses ECS motherboards in the computers it builds. The ECS motherboards are suitable for business use. They may not be the best for overclockers or gamers.
I wrote a long letter to Promise Technology Technical Support about the fact that Promise is allowing ECS motherboards with Promise RAID mirroring controlers to be sold without software that is necessary to monitor the health of the mirror. The letter is below, and represents my opinions at the time. Even though the national sales manager of Promise suggested I send the letter, there was no answer.
Below the letter is all information and opinions that I had available at the time.
___________________
TO:
Kevin Hong
Promise Technology Technical Support Engineer
Kevin,
Jason Turk told me to write to you about a problem with Elitegroup's L7VTA Rev. 1.0 motherboard, which includes a Promise RAID controller chip.
Elitegroup says they have never been provided the FastCheck or PAM monitoring software for this motherboard. Can you supply monitoring software that is certified by Promise to work? The software is not on the CD supplied with the motherboard.
We need not just software that appears to work, we need software that is certified by Promise Technology to work with this motherboard. Several people at Promise have told me that the software provided on the Promise web site for the Promise RAID controller adapter cards may not work with the OEM controller chips installed on motherboards. I suspect this is not true, but merely a Promise Technology marketing scheme. However, we can't risk selling these to our customers and finding later that there is some hidden serious defect.
Thanks,
Michael Jennings
Futurepower Computer Systems
_______________________________
Complete Information:
So that all the information to resolve this issue is supplied in one place, I have provided everything that I know and think below:
Some versions of the Elitegroup L7VTA Rev. 1.0 motherboards are being supplied with Promise Technology's PDC20265R IDE RAID controller. Elitegroup supplies three of the four elements needed for a RAID controller. The motherboard and included CD have 1) Promise Technology's PDC20265R ASIC chip, 2) the latest version of the BIOS, 3) and the driver software.
However, item 4 is missing. Elitegroup says Promise Technology never supplied RAID array monitoring software for this chip. Promise Technology calls this software the "FastCheck" or the "PAM, Promise Array Management" utility. Without this software, the user cannot know if a hard drive has failed in the RAID 0 or RAID 1 or RAID 0,1 array.
This issue is Elitegroup's Case number RAE54616. (Note that Elitegroup also calls themselves "ECS".)
Elitegroup's web page for the L7VTA product is here:
http://www.ecs.com.tw/products/pd_spec.asp?product _id=327 [ecs.com.tw]
The L7VTA V1.0 driver page is here, showing the latest Promise drivers:
http://www.ecs.com.tw/download/dw_spec.asp?product _id=63 [ecs.com.tw]
Promise Technology's web page for on-motherboard RAID controllers is here:
http://www.promise.com/product/oem_ataraid_pdc2026 5r_eng.htm [promise.com]
Note that this Promise web page mentions all four elements of a
Gimme a break. (Score:5, Insightful)
If you want to go cheap, you're much better off using Windows 2000/XP's dynamic drives/mirroring ability in software.
I never will understand why motherboard manufacturers use Promise/Highpoint chipsets on their "high-end" or "server" boards. Complete waste of time.
Software RAID (Score:3, Interesting)
Software RAID has many advantages. You can monitor everything about the RAID array from within Linux. Drivers are no problem. It is well-tested and stable.
Also, you can get better performance. I would rather spend an extra $200 for a dual-CPU mobo, get a second CPU, and run software RAID, than spend $200 to get a dedicated RAID card.
Re:Attention j3110: You're Dumb. (Score:3, Insightful)
Also, I've had a Seagate that wasn't very tolerant of interference. It was getting CRC errors about 10+/s without a good shielded cable.
I don't know what tests you've seen, but the tester must have been an idiot. Run four IDE devices (at different speeds) in your box with the crappy standard ATA66 cables,
These are not RAID Cards, they are Accelerators (Score:5, Interesting)
With that said, if you're going to do software RAID, you might as well just do it. I've been using VINUM on FreeBSD for a long time, there are other options for FreeBSD and for Linux. The better ones take full advantage of the "dual read" property of mirrored drives at the kernel level. Best part, no special hardware required. If something breaks buy any old ATA card and you're back in business since it's all in software.
If you need RAID-4 or RAID-5, a dedicated card might be a good idea. For mirroring I think software is superior.
3ware support story. (Score:4, Interesting)
Until the 3ware, I had been "The SCSI guy" in most circles. I was running all scsi systems starting in 1992 and woe betide he who suggest I add an inferior IDE device to my system. I had first spotted the 3Ware at PC Expo back when they were prototyping the 6000 series, and immediately scoffed at it as "just another IDE RAID wannabe." The 3Ware engineers overheard this and invited me to come over and play with their system and tune the benchmarks on it (standard ones like iometer, not custom in house things you can fake easy) to prove they were serious. I left their booth saying "I want one!" and repeating it to my friends for the rest of the show.
But I digress. I had purchased a 3ware, to go in my new Athlon system. This was back in the old Slot A athlon days with the bad AMD750 chipsets. I had an Asus K7M, and the 3Ware was not cooperating. After a few hours of fighting with it, I put it in my trusty celeron system with the BX chipset motherboard. It still didn't work, so then I knew I had a problem. This was unfortunate considering I was leaving for college on saturday, and this was thursday afternoon.
So I called 3Ware. I described the problem and had very little trouble (for once) convincing the tech support guy I wasn't some kind of moron. They believed me when I said I knew what I was doing when I put a system together, unlike most other companies. After an attempt to flash the card's BIOS to a good image, they said that the card most likely had a defective chip and would need replacement. They said they would gladly do it but their RMA system was down due to a server problem, and that calling hypermicro back would be the best option.
So I called Hypermicro, and they say they'll be happy to get me a new card, but there's no way they could get it to me overnight (as it's now late afternoon). I explain the problem of leaving for college and they say they'll be happy to ship it to me when I get there. I wasn't happy about that.
So I called 3Ware back, and explained what Hypermicro had said about being unable to replace the card before I leave. It's now about 8:30pm NY time, Hypermicro I believe is in central time, and 3Ware is on pacific time. The 3Ware support guy brings his manager on the phone (I didn't ask), and the manager says "Give me your information, and I'll have a card there for you. Send us your defective one back when you get a chance." So, 3Ware sends me a retail box card with the cables and all as a replacement for my OEM bare card, cross shipped, without an RMA number, and has someone take a car and speed to the FedEx hub in person to get it shipped.
10AM NY time the next morning the card was there.
The new card worked perfectly, and I was very happy with it. About 2 months after I bought it, 3Ware sends me an email. It basicly says the following: "We have implemented RAID5 support for your card in our new driver and firmware. You may download it as a free upgrade even though we had only planned to support RAID0, 1, and 10 on your product." How's that for support and driver updates?
Also, after the 6000 series was retired in favor of the 7000 and 7500s, 3Ware sends me another email that basicly says "We know your cards are considered obsolete and no longer made, but here's a free driver that adds > 137GB disk support to your ata-66 level controller that shouldn't officially support that standard." And at that point they'd basicly retired the products, yet they were still developing new drivers and firmware for their obsolete parts!
I now own a 7500-4 as my main controller, and I will likely be buying one of the 9000 series SATA-II controllers when they come out as an upgrade.
Oh and I've never missed my DPT (unfortunately since bought and ruined by Acraptec) with its hardware RAID5 and cache or my seagate cheetahs or any of my other SCSI hardware ever since.
Promise "RAID" (Score:3, Informative)
As such, there are three ways of getting them working with Linux:
Use the Promise RAID driver
Use the Linux ATARAID driver
Use the Linux md RAID implementation
The first of those is handy if you're dual-booting with a RAIDed Windows installation and want everything to work. The disadvantage is that you'll be limited to certain kernel versions as other posters have already noted.
The second option also allows interoperability with other OSs RAIDed on the same drives, but because the drivers aren't written by Promise, there may be some gotchas. The advantage is that ATARAID comes as standard with all Linux kernels, so you'll never be forced to lag behind through lack of driver availability.
The third option is probably the most stable and convenient, as long as you don't require another OS to use the Promise RAID setup (md has not been ported to Windows, as far as I know!)
I chose the md option as although I do dual-boot with Windows, I don't have any important information stored there. Note also, that because all the smarts are done in software, there's no inherent performance overhead in using md over Promise's driver.
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Re:I run Linux on my 500 client network server (Score:5, Informative)
Assuming you didn't mean that as a troll...
HDD mirroring generally provides protection from *hardware* failure, not software glitches. If Windows suddenly decides to overwrite your porn collection, a RAID controller will faithfully do it on both drives. If you accidentally do an "rm -rf
Parent
Re:Uhm, correction (Score:4, Interesting)
Does RAID 1 specifically require that, or would that count as an implementation-specific detail?
Because, if implementation-specific, I see no reason why RAID 1 couldn't use the same striped request pattern, since the desired data will exist on both drives anyway (ie, a proper superset of the data available to RAID 0). That wouldn't speed up writing, but for reading, you could get the same benefit as RAID 0.
Parent
Re:Why are drivers needed for RAID? (Score:3, Informative)
AFAIK you build your raid array for say mirroring using the bios of your raid chipset (promise for example). Then it makes sure that any write to hda is actually also a write to hdb. So I think it's purely a bios issue and nothing for the OS to do...
NT and Linux don't use the BIOS at all once the kernel has loaded into memory. The BIOS is only used for booting off the controller. It's also probably the same on OS/2, BeOS and *BSD - Win9x was a bit of
Re:Why are drivers needed for RAID? (Score:3, Informative)
What's the point of that? I've always looked at hardware RAID with a sideways glance because of designs like that. None of these 'low-end' cards really advertise the fact that they are crippled in that way, either.
Wouldn't it be more redundant and just as fast to have two regular IDE controllers and just use the RAID capability of the OS? I always thought that when the drive goes, there's a fair probability that it will take the controller down with
Re:$80 is expensive? (Score:3, Informative)