The Amazing $5k Terabyte Array 448
An anonymous reader writes: "Running out of space on your local disk? How about a Terabyte array for only a few thousand dollars. This article at KCGeek.com shows how to put together 1000 Gigs of hard drive space for the cost of a few desktop computers."
I could rip my entire anime collection for instant access! Rip all my
CDs and still have .9 Terabytes left! Maybe Mirror Usenet! I guess
the simple truth is that now that 100 gig drives are a couple hundred
bucks, we now have the ability to store anything we reasonably could
need (unless you define "Reasonable" as "I need to store DNA Sequences").
I'm sure I'll figure a way to fill it... (Score:4, Insightful)
Its only a matter of time 'til video becomes as commonplace as MP3's on our drives. 100 Gigs is what...20 movies??? I don't see my appetite for disk space slowing down any time soon.
Hmmm...video; logfiles that don't roll over - ever; online network backup... I'm sure to figure out a way to fill that terabyte. :)
Re:I'm sure I'll figure a way to fill it... (Score:2)
Seriously , the big problem here is not having the data online, but figuring how to recover it if you lose it.
Not that RAID is a bad thing, but I have seen RAID systems go down - I lost a day's work (not archived by myself) when my web hosting company's raid system failed completely. (They were most apologetic and offered some compensation, but the data was very gone for all their customers - I believe they bought new RAID systems from another vendor immediately thereafter).
My 2c worth.
Michael
Re:I'm sure I'll figure a way to fill it... (Score:3, Insightful)
Code Versioning/document management on changing files to maintain history.
Your web hosting provider had 1 Raid system, thats only 1 level of redundancy (I know multiple disks - but on 1 system). If you want to truely ensure data you need redundant systems, such as networked backup to 2 additional machines that also utilize raid.
If the data is critical you need to examine points of failure. Thats what clustering, and load balancing offers - total redundancy.
Re:I'm sure I'll figure a way to fill it... (Score:2)
I once saw a shaddowing controller fail in such a way that it managed to corrupt both of the RAID 5 arrays it was driving. Had to bring the system back up from the first level backup.
Soon after that we switched to using EMC gear.
The Amazing $5k Terabyte Array (Score:2, Interesting)
you can do it with 6 drives vs. 10 drives,
and alot of motherboards come with onboard
RAID, and if you use software RAID via
win2k or Volume manager type app for Linux
it would rock .
Cheap too, at $260 per drive per pricewatch .
Peace out...
Re:The Amazing $5k Terabyte Array (Score:2, Offtopic)
If I had to store a terebyte of information I'd be an idiot to use consumer level storage (IDE).
Ever wonder why real servers uses SCSI?
Re:The Amazing $5k Terabyte Array (Score:3, Informative)
I agree that on a server or a professional workstation SCSI is the way to go for speed and reliability. But for the home consumer who wants to work with digital video the cost of a SCSI RAID set up is extremely prohibitive.
Re:The Amazing $5k Terabyte Array (Score:2, Informative)
I do wish to avoid yet another SCSI/IDE flamefest, but I would point out that this configuration is like most of its ilk--it is basically network attached storage. That means that no one will be reading or writing from the server system itself, but will be accessing the raid array through a network link via NFS and/or SMB. In my experience, performance of Linux Software RAID5 on Promise IDE controllers with 80-GB Maxtor 5400-RPM hard drives can exceed 50 MB/s write and 70 MB/s read. SMB/NFS even over Gbit ethernet will be hard pressed to saturate that.
Having built many of these low-budget raid5 arrays, I cannot concur that SCSI and/or hardware RAID is necessary to see acceptable performance. <Horror stories about Hardware IDE RAID5 controllers deleted.>
I do admonish would-be builders to include an extra hard drive in the raid array as a hot spare. For four drive arrays (3 data + 1 parity), it may be unnecessary. For larger system (7 data + 1 parity), I think a hot spare is a worthwhile investment. Also, avoid 7200-RPM drives if possible and actively cool all of the drives in the array. One or two fans blowing on the array can make a big difference.
Re:The Amazing $5k Terabyte Array (Score:2)
This is important in any drive array. IF you dont have them spaced apart and have cooling fans on them, no mater what they are, you are asking for failures and short life spans. I was am azed at the differences on my SCSI drives, seperating them another 1/4th of an inch and adding a fan blowing at each bundle of 3 drives caused a temperature drop from 110DegF to 76DegF or only 4 degrees above the server rooms ambient temperature. (Hey, I'd rather have it set for 60 but the traffic and billing ladies complain..they keep their work area at 80!)
The suprising part is that the ML530's have a spot to place a fan in the drive cages, yet no fans installed.
Re:The Amazing $5k Terabyte Array (Score:2)
The performance is questionable. IDE is behind SCSI, but not nearly as badly anymore. And how are you accessing this storage space typically? Through a network whose speed is likely not to exceed 100 MBit, so network is essentially the bottleneck for throughput, unless of course you have some data processing application or something like oracle, in which case your point may be valid, but still, SCSI is still overpriced for what it gives... If only it had prevailed more, then it would be cheaper and this debate would be moot...
Re:The Amazing $5k Terabyte Array (Score:2)
They really really need to design a IDE-II specification that gives the SCSI performance traits to IDE.
Re:The Amazing $5k Terabyte Array (Score:3, Interesting)
> specification that gives the SCSI performance
> traits to IDE.
They already have it -- tag command queueing has been in the ATA spec for years, since ATA-5 I think. Most vendors either have command queueing IDE drives, or are coming out with them soon.
http://www.t13.org for more info on the various ATA specifications
--eric
Re:The Amazing $5k Terabyte Array (Score:2)
I've built a 1.04TB array. It's an impressive hack of a system. Out of the 16 drives for the array, four (4) were defective right out of the box! And two of those replacements were suspect. After a month of handling a full news feed (120G+ per day) we've worked most of the kinks out of it (I don't recommend w2k for a drive array.)
BTW: I used a pair of 3ware Escalade (6800) controllers. They take alot of the suckiness out of IDE (tho' it's a cabling mess.)
3ware and external raid devices (Score:3, Informative)
I don't know how he does it, but I have personal experience in doing it two different ways:
1) 3ware IDE RAID controller, has 1 IDE controller per drive on the card (i.e. 8 ide controllers), which the firmware maps to a RAID Device. Depending on the RAID configuration the drives appear as one large SCSI drive to the system.
Performance is on par with SCSI.
2) External IDE-SCSI Raid chassis. Again, 1 IDE controller per hot-swap drive, appearing to the system as one or more big SCSI drives, controlled by a standard SCSI controller. Speed and reliability have surpassed that of a $60,000 SCSI solution sold by Sun I happen to have lying around.
U160 SCSI drives will give you at least a 70% speed increase and a 80% increase in reliability....
If I had to store a terebyte of information I'd be an idiot to use consumer level storage (IDE).
Nonsense, see above. This is simply SCSI bigotry (I know, I was once a SCSI bigot too). What you say is only true if you are using low end cards, with more than one device on each IDE bus, which is untrue for mid- and high-level IDE-SCSI solutions such as 3ware and various external chassis systems. We run our entire enterprise on one, and have done so for well over a year, with much better reliablity and performance than an older, very expensive SCSI solution provided.
But yes, if people are plugging drives into el cheapo IDE "raid" cards like Promise and the like, or worse, into their onboard IDE controllers (most of which are inexpensive knockoffs anyway) then performance will be very suboptimal, and reliability problems (one device taking down the entire IDE bus, etc.) abound.
Re:The Amazing $5k Terabyte Array (Score:2, Interesting)
Actually (Score:5, Interesting)
Re:Actually (Score:2)
Re:Actually (Score:4, Funny)
But be careful with that compression thing! If you compress the DNA too much, you could end up like Minime [geocities.com]
Re:Actually (Score:2, Interesting)
Re:Actually (Score:5, Insightful)
You are correct that the human genome is "only about" 3 giga basepairs of sequence, but to only store that would be rather egocentric. There are as of Dec 3 2001 some 14396883064 bp in the GenBank, and the amount of sequence information [nih.gov] still grows roughly in a exponential manner.
Now, this will not hit the TB line anytime soon. The trouble starts if you are involved in genome sequencing. Then you need to store the raw data for all that sequence. Each some 450 bp of sequence is reconstructed from about 5 - 10 different fairly high reslution gel images (in the ballpark of 150 kBi per image). Also, recall that even short stretches of the sequence can be accompanied with a lot of annotating information, such as names and functions of genes, regualtory elements or pointers to articles explaining the experimental evidence for such. This mutiplies the storage requirement with quite a factor - nothing a neat little linux box with a huge RAID-array cannot handle though. Thats how we handle the sequencing data from Trypanosoma cruzi, by the way.
Re:Actually (Score:2)
CATcoyboynealGTTA....
"I need to store DNA Sequences"??? (Score:2, Informative)
human = 3 billion base pairs
= 6 billion bits of data
= 7.5e8 bytes
= 7.3e5 kilobytes
= 715 megabytes
< 1 gigabyte
Sure, lots of other life forms have been sequenced too, but most of these have much smaller genomes than humans.
So how would you need a terabyte to store DNA sequences?
Re: "I need to store DNA Sequences"??? (Score:2, Insightful)
Use "MPEG": people differ by 0.1% (Score:2, Interesting)
Re:Moore's Law and bioinformatics (Score:3, Funny)
In fact, the EMBL database (all known DNA + protein sequences) nearly tripled in size within the 11 months of Nov. 1999 - Aug. 2000 [Stoesser, 2001]. Shake your Moore's law at that figure, matey.
Need for memory/storage (Score:5, Funny)
Nobody should ever have need for more than 640 kB of RAM Bill Gates
Simularities anyone?
Re:Need for memory/storage (Score:3, Funny)
Personally, I won't be satisfied until I have enough storage to catalog the quantum state of every particle in the universe.
Re:Need for memory/storage (Score:4, Funny)
thousand hours of video? (Score:3, Interesting)
I don't include the argument that you'd have trouble finding old stuff. Computer software is more clever at organizing things - far better than material storage. A good recent example of this is Apple's "iPhoto" that much more convenient for organizing thousands of photos than physical albums.
Re:Need for memory/storage (Score:3, Informative)
QUESTION: "I read in a newspaper that in l981 you said '640K of memory should be enough for anybody.' What did you mean when you said this?"
ANSWER: "I've said some stupid things and some wrong things, but not that. No one involved in computers would ever say that a certain amount of memory is enough for all time."
Re:Need for memory/storage [OT] (Score:2, Informative)
Cost Per MB (Score:3, Informative)
$ 5,000
Or another was $4.88 for a GB.
Now who remembers when harddisks where more than $10 a mb.
Re:Cost Per MB (Score:2)
(See, for example, the note on http://maxtor.com/products/diamondmax/diamondmaxp
Therefore, in *this* case, 1TB = 1000GB = 1000000MB, which puts the price up a little (although not much, I'll admit
Cheers,
Tim
Re:Cost Per MB (Score:2, Insightful)
1 Terabyte = 1000GB = 1000000 MB
Their marketdroids have a bad habit of rounding the values down and evening them off. This allows them to post bigger numbers on the actual size of the drive since dividing by 1000000 instead of 1048576 yeilds a larger end result.
Re:Cost Per MB (Score:2)
Nothing special. (Score:2, Interesting)
U160 and all of it churning at 10,000RPM. For a grand total of a few GB short of 5.5 Terabytes.
But assuming you can affoard Thirty 1200$ drives you should be able to spring for a nice U160 SCSI RAID Card with an external connector
I couldn't even find a case with enough room for 30 hd's.... and I don't want to even think about cooling.
But I wont have to worry about that. I can't even affoard a 9gb scsi drive at this point.
Re:Nothing special. (Score:2, Interesting)
Heard a rumor that they may be considering support for IDE in something like this.
Re:Nothing special - bullsh*t (Score:2)
2. SCSI drives don't turn into slugs when you access more than one at a time. IDE does. Want to see it REALLY screw up, access an ATAPI CD-ROM slave the same time as a HD Master on the same controller.
3Ware Escalade IDE-RAID (Score:5, Interesting)
$500 for an 8-port 64-bit RAID controller, looking to the host like a single scsi device per logical volume, seems like the best deal available. Along with a motherboard with sufficient slots for gig-e and these cards (easy to get 4 64-bit slots...maybe you can get more with 3-4 buses), and a 4U rackmount case with 16 drive bays, and you can have 4U of rackmount storage for $5k, too.
I've been using setups like this for clients, as well as for private file storage (divx, mp3, backups, etc.), and know of people using them for USENET news servers (one of the most demanding unix apps for reasonably priced hardware).
It goes without saying you want a journaled file system or softupdates when you have disks this size, and ideally keep them mounted read-only, and divided into smaller partitions, whenever possible. e2fsck on a 300GB partition with hundred of open files is painful.
3ware is Painful! (Score:2)
First, there were hardware bugs and they recalled the controller
Second, 3ware dropped the product line, but vendors were still telling me it was available.
Third, they brought it back, and I had to get a drop ship
I lost about 3 months on design phase due to this little tidbit.
Now don't get me wrong, it's working now and seems reliable... but... there's always this nagging suspicion that something is going to go wrong and I'll lose all that data.
Great! Where's the backup solution? (Score:5, Insightful)
Yes, this is a groovy/geeky/cool solution for under your desk, but at least spend the extra dollars for a SCSI card and tape backup unit. You could fit the whole thing on a few DLT's. You can also keep incremental backups to keep the tape swapping to a minimum.
Re:Great! Where's the backup solution? (Score:2, Insightful)
Re:Great! Where's the backup solution? (Score:2)
Re:Great! Where's the backup solution? (Score:2)
Re:Great! Where's the backup solution? (Score:2)
Re:Great! Where's the backup solution? (Score:5, Insightful)
FIRE!
Any serious data store needs to include a backup system which allows for copies off-site. Fire is the obvious risk of course, but floods, vandalism and lightning strikes are all possibilities.
AFAIK the only generally available tape backup for something this big is DLT, which IIRC can now do around 40GB per tape before compression. With the 2:1 compression usually quoted thats 80GB per tape, or around 13-14 tapes for a full backup. So you really need about 30 tapes for a double cycle, and maybe more if lots of the data is non-compressible (like movies). But this stuff ain't cheap. DLT drives start at around £1000 and the tapes cost £55 each. So thats around £2500 = $4200 to back this beastie up.
Having said that, the possibility of using hot-swappable IDE drives as backup devices is intriguing. Just point your backup program at /dev/hdx3 or whatever. One big advantage is that if your tape drive gets cooked in the server-room fire you don't have the risk of tapes that can only be read on the drive that wrote them. A Seagate 5400RPM 60GB drive costs £110, which is only a third more per megabyte than a bare DLT tape. Two cycles-worth of backup (34 drives) would be £3,700. And you can probably do better by shopping around. For servers with only a few hundred GB on line this might well be more cost-effective than buying a DLT drive.
We use Amanda [amanda.org] to do backups here. Its a useful program, but it can't back up a partition bigger than a tape. So you need to think carefully about your partition strategy. (Side note: you can use tar rather than dump to break up over-large partitions, but its still a pain).
Suddenly that terabyte starts looking a bit more expensive.
Paul.
Oops! (Score:4, Interesting)
Does anyone out there actually use IDE drives like this? It seems a pretty obvious thing to do.
Paul.
Tape is better for backup... (Score:3, Informative)
With tapes, you just get a new drive.
Re:Oops! (Score:3, Informative)
I haven't tested it out but StorageTek has a drive called the 9940 which has tapes that hold 60gb uncompressed (likely 200+gb compressed), it writes faster (10mb/sec ~= 55gb/hour). Also, the drive itself will put you out $33.5k with the tapes being a couple hundred a piece.
In this case, it'd probably be better just to have a second 1tb raid - then again tapes are much more stable.
-Cuyler
Re:Great! Where's the backup solution? (Score:2)
Plus, as described in the article, where the point was to have a singe hard drive based storage for dvd's and cd's, if there was a drive failure, you could just take the original media and do the rip again. Annoying yes, but doable. You haven't lost data unless the fire burned down your house and melted the cd's at the same time it took out your storage. That's why companies buy fire safes and use off-site storage.
Re:Great! Where's the backup solution? (Score:2)
A much better article, also pointed to by /. (Score:5, Funny)
The nice thing about this article is that the people building it at SDSC really took extreme care in getting quality components that would work together to build a reliable, solid system, and still didn't spend more than $5K for a terabyte file server. In particular, the tradeoff of disk speed vs. power consumption was extremely insightful.
I built one of these to their spec for my company, and I couldn't be happier. It's worked flawlessly since then. It's not clear if the Escalade boards are still available -- 3ware had said that they were discontinuing them, but they still appear to be for sale.
thad
Re:A much better article, also pointed to by /. (Score:2)
Re:A much better article, also pointed to by /. (Score:2, Informative)
Promise FastTrak 100TX2 * 4 $500
Maxtor DiamondMax 160GB Drive * 8 $3000
Maxtor DiamondMax 20GB Drive $80
You can get an Escalade 7850 for $550 or less, which is a single 64-bit card instead of the 4x Promise controllers. I don't know why there's a 20GB drive in there, maybe a boot drive? At $3k for 8 160GB drives, that's $375 each. Looking quickly at pricewatch, you can get the same Maxtor 160GB drives (5400RPM -- yuck!) for around $260 each. 8*160*(1000/1024) = 1250MB (actual MB) = 1.22 TB for a total of 550+8*260 = 2630 instead of 3580. Plus you have 3 PCI slots more than you had before.
It's just IDE Raid 5 folks.... Move along. (Score:2, Informative)
http://www.acnc.com/04_01_00.html
Re:It's just IDE Raid 5 folks.... Move along. (Score:2)
Re:It's just IDE Raid 5 folks.... Move along. (Score:3, Informative)
Re:It's just IDE Raid 5 folks.... Move along. (Score:2)
Re:It's just IDE Raid 5 folks.... Move along. (Score:2)
Depends on the RAID controller. Some-- although damn it because I can't remember their names-- do parity on the read and on the write for an extra level of error checking. The idea is to catch bad data before it gets to the OS.
How to use the disk space (Score:4, Funny)
1) "Compress" at a higher rate than the CD uses (I've seen this)
2) Use POV Ray to render Lord of the Rings for the cinema
3) Keep every src and every
4) Set the Linux swap space to be "500Gb" because you've upgraded the Kernel to the new VM stuff and it looks cool
5) Install Windows XP+ in two years time, with Office XP+.
Imagine that "Minimum Reqs: 1TB of available disk space"
It will happen
Re:How to use the disk space (Score:2)
1) It isn't compression its stupidity.
2) Just because POV is slow doesn't stop a 3 hour movie at Cinema res using multiple terrabytes of disk space. Anyway Beowulf cluster POV for speed
Redundancy? (Score:2, Interesting)
What we need isn't larger hard drive storage (not that it's a bad thing) we need more speed, and a cheap, gigantic & ultrafast tape backup system to backup all the data. Some PC designs that use better cooling methods would be very nice as well.
Re:Redundancy? (Score:2)
Re:Redundancy? (Score:3, Insightful)
They could also do what we did with our IDE TB. We used three RAID5s in hardware, each with hot swap. In theory, if they failed just right, we could lose up to 6 drives without losing any data.
The three RAID5s are hardware RAID0ed together. The worst case scenerio is a simultaneous failure of two drives on the same array. But we saved so much money using IDE that we just built two complete systems for less price than SCSI. So really, we would have to hit the worst case scenerio twice at nearly the same time to have a total loss.. It gets less and less likely.
Done before (Score:2)
64 bit address space (Score:2)
2TB for $8300 (Score:5, Interesting)
Story here [smythco.com]
As far as performance:
(from my memory)
EXT3: About 16MB/Sec block write, 45MB/sec block read
ReiserFS: About 20MB/sec block write, 130MB/Sec block read (that's no typo).
XFS: About 30MB/sec block write, 85MB/sec block read.
It seems that file system plays a large role in performance. The arrays are three RAID5 in hardware using Linux software RAID0 on top of the RAID5 arrays to tie them together.
IDE RAID controllers are 3ware Escalade 7810. Write performance can be greatly increased by using 7850 cards that have more cache.
We stuck with XFS, Reiserfs had a bigfile bug, files created over 2GB would lock up the computer basically. XFS in general seemed much more mature, reiserfs seems more like someone's college thesis project, that they never cleaned up to be production grade.
We experimented with different RAID0 stripe sizes, the hardware RAID5 stripe size is fixed at 64k, there are 7 active disks in each array and one hot spare. Stripe size tweaking seemed to mostly trade off read for write speed, within a certain range of values, with a taper off in performance at either extreme, (down around 8k stripes, or over 1024k stripes)
We eventually went with 1024k stripes. That is what the benchmarks above reflect. The variance in file system performance could very well be due to interactions with stripe size, but there seemed to be common themes (reiser always read fastest no matter what stripe, XFS was always better at writes)
I have been in so many arguments with SCSI zealots on here over this RAID... I wish people would understand what price/performance ratio means. IDE isn't a superior technology, but every now and then, it is the right tool for the job, when price is a goal too.
Uhm, redundancy in posting? (Score:3, Interesting)
slashdot announced an amazing terabyte arrayHere [slashdot.org]
Seriously though.. People's numbers are pretty far off. This can be done for about 3000.. Pricewatch
has 160 gig drives for $259
Lately I'm realizing how awful IDE really is.. I finally got around to throwing 2 36 gig ultra 160 drives on my box with an adaptec scsi card, running ext3 on top of a raid mirror.. more space than I need (I just keep all my mp3s on an IDE raid.. since my dragon motherboard has ide raid built in).. Since I've gone to scsi life has been happy. I can do things while compiling, while vacuuming my db, etc..
Funny how mac used scsi before the rest of us, huh?
Re:Uhm, redundancy in posting? (Score:2)
And as far as this story is concerned, the array I plan to build happens to cost about 1100 dollars and provides 480 gigs of storage (160 more is redundancy, so if redundancy wasn't an issue, it would be 640 gigs, and as we all know, "640 Gigs ought to be enough for anyone"), so a $5k terabyte seems a bit steep when you think about it.
YKYHBRSFTLW (Score:2, Funny)
The first thing that runs through your mind when you see the above headline is: "Wow, imagine a Beowolf cluster..."
Argh.
4 Controllers for $500? (Score:2)
This neat piece DOES hardware RAID5, so you don't need a fast cpu&mobo, less RAM, and since it can only manage up to 6 drives you can even have 2 as pseudo hot spare...
The only drawback is the ability of "only" storing 800GB which is nice at this even cheaper price...
Why use expensive online storage? (Score:3, Interesting)
Why not use slower but MUCH cheaper offline storage? I really like the design goal of
http://www.dvdchanger.com/
You can easily get 1TB of storage with such a device for less than $1000. True, only one person can access it at a time but that is only because PowerFile wants to charge more for so-called "networked version".
In theory, if someone could figure out how to build on of these things, you could throw in a two or three CD/DVD drives for accessing and a 20GB hard drive to buffer images. Boom. Now you have the perfect storage backbone for a house-wide media center. I just wish Linksys or someone would throw a linux thinserver onto of the PowerFile hardware and get me something cheap and network-ready.
- JoeShmoe
.
Why not firewire? (Score:3, Insightful)
I figure this is the easiest way to add as you grow without having to break open the case and try to figure out how to add another damn drive in there. For backup, just have two systems with identical capacities and rsync between the two nightly.
RAID is nice, but for home use, it's not as nice as a nightly mirror. Why? I've seen RAID controllers fail and take out an entire RAID set. RAID also doesn't deal with the "Holy shit, I just accidently type `rm * ~` instead of `rm *~` problem."
Re:Why not firewire? (Score:2, Informative)
9.9 TB = approx 0.01 PetaByte
Don't hold your breath thinking about petabytes.
Also, RAID isn't for people who make stupid mistakes. Sorry about your 'rm' debacle.
DNA Sequence (Score:2, Informative)
Home File Server Appliance (Score:2)
Re:Home File Server Appliance (Score:2, Interesting)
I settled on using 802.11b wireless to communicate between the house and the office. I know all about the security problems (my address is....) but maybe the newer 802.11g or 802.11a might work for you.
I have some workbenches in the basement that are about 4-5 feet off the floor. I'm going to install a file server and leave it on one of these benches.
It's cold and damp down there in the winter. I don't know how well the equipment will take to the humidity. I guess I'll find out!
Ouch! $160GB disks! (Score:5, Insightful)
A final word of warning: Promise ATA100 TX2 controllers may look like a natural choice for a server like this, but they only support UDMA on up to 8 drives at once, and Promise's tech support only supports a maximum of 1 (one!) of their cards in any system.
Mirror Usenet? (Score:5, Funny)
Re:Mirror Usenet? (Score:4, Informative)
Re:Mirror Usenet? (Score:2)
But it can't fit inside a lego brick!!!!!!!!! (Score:2)
Drive Failure Notification Problem (Score:2, Interesting)
How do you know WHEN a drive has failed?
With the low end IDE RAID cards your notification comes when the 2nd drive fails......
3Ware's website describes a SNMP monitoring utility for windows, but didn't specifically mention Linux support. Ditto for Adaptec.
If the raid is done in software, is there a linux program to monitor and notify when a single drive goes down?
Cheaper and more redundant if you use 2 .5 tb serv (Score:2)
2 xp processors = $220, mobo = $220, memory = $200,
case = $150, total is about $1500 for
i/o bandwidth with 6 ide controllers, and 2 pci busses than with the single. Also when one of them craps out, the other is still going in all probability. Going to 80 mb drives gives you about the same cost per gb of drive space and lets you put
Even cheaper (Score:2)
Now I just need to find $2500. I know I won't have a problem filling it.
-Restil
gawd (Score:4, Funny)
There's a reason they called it "Terraserver" (Score:3, Interesting)
Of course these days I'd want 3TB so I could store color images.
The price... (Score:3, Funny)
All the pr0n you could ever watch - $1,000,000
The look on your Mom's face when she clicks on AsianDogAssRape10.mpg - Priceless
The Antec case is not good for ide raid (Score:3, Informative)
For IDE raid, this case is good except it's a bit expansive:
http://www.rackmountnet.com/rackmountchassis/ra
It can hold up to 16 drives with hot swappable trays. There should be no cable length problem.
On a side note, I used to plugin 5 Promise Ultra100TX2 cards in one computer. All cards are recognized but only 8 drives are recognized correctly (I plugged in 12 drives altogether). I remember seeing some where (either in linux kernel source or FreeBSD sys source) saying that Promise has a limit of 12 drives per system, with 8 of then in DMA mode, and the rest 4 in PIO mode with some tweak (burst?). So for a big raid like that, an ide raid cards (either 3ware's or high point's) are recommended. Using a hardware raid ide card also has the benefit of being able to hot swap the drives with the case mentioned above.
Do it for half with Pricewatch (Score:3, Interesting)
Better performance.. (Score:4, Interesting)
the TX2 is a nice little card, but you can only use 2 drives per board for getting the "full speed" (else if you use master/secondary, 4 drives will give you the raid speed of 2 in stripe) and then you'd have to stripe your raid-0 drives in software. Instead of wasting PCI slots and using an underperforming card, you pay a couple of bucks more and you get the real thing with full speed and hardware raid5.
There are a lot of raid benchmarks at storagereview.com as well. IDE raid is so damn cheap.
raidweb (Score:3, Informative)
http://www.raidweb.com
We purchase their 8 disk IDE RAID arrays. They are hot swap, support RAID 0, 0+1, 1, 3, 5, and hot spare, have dual failover power supplies, come with 64MB cache, which can be upgraded. Configurable via the EZ front LCD display, or via serial console. They support ATA-100, and ATA-133 coming shortly. Software upgradable, and it runs Linux.
They array (sans disks) runs us $3200. They even have versions that have dual fiber ports out the back.
WARNING - DO NOT purchase these with IBM GXP75 (75GB) disks like we did... we have about 80 of them that failed.
Re:RAID (Score:2)
But to answer your question, it looks like an IDE Software RAID5.
Re:RAID (Score:2, Insightful)
All he needs are two of maxtor's cards, which you can buy packaged with the drive for an extra $13. Not only that, but his prices on hard drives are way too high. 8 drives (2 with maxtor's ide cards) are $2122, per pricescan.com. Since he lists $500 for the ide cards and $3000 for the HDD's, that's a savings of $1378.
Then, he quotes $500 for 2 GB of ram. At $70/.5GB sticks that's $280. $500 for a case??? Try $365.
That said, the $5720 price he quotes is high by $1733. You could build one of these for just under $4000.
Ok, I admit, I didn't include shipping.
Re:RAID (Score:5, Insightful)
> Promise FastTrak 100TX2 raid controllers. WTF?
> First off, each of those cards supports 4
> drives on 2 channels... Why does he need 4
> cards when he only has 8 drives? He only needs
> 2 cards.
I'm a firmware engineer for Maxtor... if you're going for performance, you want 1 drive on each bus, and you don't want to use the motherboard connectors. With 2 drives on each bus, you are limiting the average transfer rate out of cache to 50% of the max transfer rate. On a modern drive with their 60-65MB/sec channel rates, you cannot stream sequentially off of 2 drives without saturating an ATA-100 cable. Even running ATA-133 won't help starting a year from now.
Additionally, every bios I have looked at sucks in terms of performance. In most cases they have small DMA FIFOs which stutter the pipe during high speed transfers -- they literally hang the DMA lines while they empty their fifo into memory, then come back and grab another 8 words or something sad. They also tend to be very poor managers of the IRQ line. This causes delays at times when your hard drive could be giving you more data, but the host hasn't gotten around to asking for it yet.
All the 3rd party cards have like 2Kbyte FIFOs which prevents any overrun from occurring, which alone is quite helpful in high bandwidth applications.
The cards we include with our drives are in the lower end of Promise's spectrum... you can spend more and get more performance if you want to, which is what I suspect the author of the original article did.
--eric
Re:RAID (Score:3, Informative)
RAID ain't "secure" (Score:2, Informative)
extend that to safe-as-long-as-only-one-hd-fails-and-you-never-e
Always remember: data that is not backed up might as well not be there in the first place!
Sorry, I just couldn't resist... (Score:2, Funny)
12 Maxtor 160gb ata133, 270$ each
1920gb of Pr0n and other goodies, priceless!
Re:Inquiring minds (Score:2)
Go here for the datasheet [promise.com]
Re:Inquiring minds (Score:3, Informative)
> depth, I only saw four addresses "reserved" for
> IDE controller use. I guess you can have any
> address, but the BIOS couldn't boot off any
> address, it has to know where to look for the
> controller. Predetermined list of 4 seems to
> ring a bell.
There are 4 addresses, but you can only boot off the first 2 in most operating systems. There are ways to get more than 4 up and running to expand to lots of drives, but not sure what OSs it works with.
> Secondly, IDE seems to REALLY hit the breaks
> when you do two independant operations on two
> drives on the same channel (say, a read on
> drive 1 and writer on drive 2).
The issue is that most ATA implementation don't support command queueing, therefore there is no bus release. Each command finishes to completion until the bus is released, while the other drive sits idle. Upcoming drives will be implementing queueing and won't have this performance limitation.
> If my 4 controller addresses educated guess is
> right, and performance does crawl, you'd
> probably want to have 4 drives on 4
> controllers, one each.
The secondary port isn't inherently slower than the primary port. However, each port uses a controller address. (0x178 or something for the first, can't remember offhand)
Best performance is achieved with one drive per cable.
> If all the above is correct, this guy is plain
> wrong. He's published, I'm not, I'm willing to
> admit defeat - where am I wrong? Do the raid
> controllers emulate being scsi hosts, run off
> OS drivers (=likely windows ones), etc?
Everything except ATA hard drives are emulated as SCSI hosts. ATAPI (the CDROM protocol) is simply a packet scsi over an ATA cable. The raid controllers also just use the built-in scsi layer in the OS.
eric
http://www.t13.org for the real ATA specs if you're curious