Google Releases Paper on Disk Reliability 267
oski4410 writes "The Google engineers just published a paper on Failure Trends in a Large Disk Drive Population. Based on a study of 100,000 disk drives over 5 years they find some interesting stuff. To quote from the abstract: 'Our analysis identifies several parameters from the drive's self monitoring facility (SMART) that correlate highly with failures. Despite this high correlation, we conclude that models based on SMART parameters alone are unlikely to be useful for predicting individual drive failures. Surprisingly, we found that temperature and activity levels were much less correlated with drive failures than previously reported.'"
Great (Score:5, Funny)
Re:Great (Score:3, Funny)
Translation: Run hot, have high failure rate. (Score:3, Insightful)
This seems to be the most relevant sentence: "What stands out are the 3 and 4- year old drives, where the trend for higher failures with higher temperature is much more constant and also more pronounced." (Page 5, Section 3.4, 4th paragraph)
Often poor communication in research pages is intended to hide the fact that the results are not very useful. The above sentence can be translated to: "If you run hard drives hot, after 3 or 4 years you will have a high failure rate."
All of our drives have their own vibration-isolated fans. Google, I recommend you do that too, based on your research results.
--
Is U.S. government violence a good in the world, or does violence just cause more violence?
Google being stupid: 2 approximately equal #'s... (Score:3, Insightful)
Translation: The number of hours the drives are powered is the same as the age of the drives, since the drives are always powered.
When two numbers are close to equal, they are approximations for each other. LOL. Is there a social breakdown at Google? Are the people who don't like to think taking power at Google?
Re:Proprietary reporting (Score:5, Insightful)
You really didn't read the article, did you? On page 3 (Section 2.2 Deployment Details), the authors state: "More than one hundred thousand disk drives were used for all the results presented here. The disks are a combination of serial and parallel ATA consumer-grade hard disk drives, ranging in speed from 5400 to 7200 rpm, and in size from 80 to 400 GB. All units were put into production in or after 2001. [...] The data used for this study were collected between December 2005 and August 2006."
What are you waiting for Google to tell you? Are you really accusing them of being evil because they did a study, described their methodology, detailed their results, presented their analyses, and published it all for anyone who is interested?
You describe their conclusions as:
But there is no contradiction at all if you are smart enough to understand. They are telling you that if SMART identifies a problem with a drive then it is very likely that drive will fail within 60 days. But in a sample of 100,000 drives, many drives will also fail that have not returned errors on SMART scans. Thus SMART is a reliable indicator of impending failure but is not a silver bullet that can recognize and predict all failures before they happen.
Next time you have access to 100,000 hard drives, can analyze patterns of failure among them, can use those failures as a benchmark against which to measure analysis tools, and can come up with better recommendations for predicting failure than this study, then by all means let us know. But if you're looking for Microsoft or Western Digital or Seagate or Yahoo to perform and publish this kind of study for free, I think you may be waiting a good long while.
So SMART is specific, but not sensitive. (Score:4, Insightful)
Sensitivity/specificity always presents a balancing act of testing, and they are usually in a push/pull relationship. If you make a test too sensitive, then you get too many false positives, and wind up over treating something (i.e. the test says it might fail so you replace the drive even though it's not going to - a false alert)
If you make the test too specific, then usually you wind up decreasing it's sensitivity, or ability to detect something. Now you get false negatives, so when the test works, you can be sure that it's accurate, but it always doesn't detect the problem.
What you want to know is the Positive Predictive Value PPV, which is determnined by the formula PPV=TP/(TP+FP). TP= true positives, FP = false positives
Also useful is the Negative Predictive Value NPV, or this formula NPV=TN/(FN+TN) where TN = true negative, FN = false negative.
What information these give are as such. If a test is positive (i.e. the drive temperature is >80 C), then it accurately will predict that the drive will fail. If the test is negative (drive temp 40 C0 then it accurately predicts that the drive is ok.
Re:So SMART is specific, but not sensitive. (Score:3, Informative)
Re:So SMART is specific, but not sensitive. (Score:3, Informative)
What he/she/it is looking for (Score:3, Interesting)
It is also interesting to note the magnificent jump in failure rates once the drives get outside the three year warrenty period. No coincidence there.
Re:Proprietary reporting (Score:4, Interesting)
The amount of positive press they get from these types of releases easily justifies the effort to polish internal reports up to a publication standard. By releasing these types of papers, others may change their buying habits, which in turn will change the products sold. Google may believe that these types of papers would cause shame, not from individual manufacturers, but the industry in a whole, and thus cause better products to be produced.
Re:Proprietary reporting (Score:3, Informative)
Re:Great (Score:3, Interesting)
What the report really shows is that SMART doesn't accurately indicate the life of the drive... if anything Google drives their hardware harder than normal users, so it should be a good testbed for predictive tools.... Google would be directly interested and probably pay a lot of money to somebody that implemented the changes this engineer said... chasing around 20k+ hard drives is an EXPENSIVE task... I'd bet Google pays a MILLION dollars a year in salary just to have somebody available to run out and replace unscheduled drive failures. That's a big process improvement that they would like to see hard drive manufactures answer.
Hmm (Score:2, Interesting)
Re:Hmm (Score:5, Funny)
Didn't read the summary? (Check)
Congratulations, you're not officially a slashdot regular!
Re:Hmm (Score:4, Funny)
Congratulations, you're now officially a slashdot regular! - Pug
Re:Hmm (Score:3, Funny)
Didn't hit the 'Preview' button first? (Check)
Congratulations, you are too!
Re:Hmm (Score:4, Informative)
So, if you have errors in those highly correlated categories your drives are probably going to fail, but if you do not have errors in these categories your drives can still fail.
Re:Hmm (Score:3, Interesting)
It isn't even that good. Many of the failure flags indicate between 70% and 90% survavability to 8 months. This is much worse than the ~2%/year baseline failure rate, but not as strong of a predictor as you might like. It would be nice to see data on this out to 2 or 3 years, so you could calculate the integrated chance of failure over the service lifetime, but by eye it looks like the trends were leveling off by 8 months.
So, if you want to avoid replacing too many good drives, you probably have to move to a multiple error model, which probably reduces your detection liklihood well below the already low 44% reported.
Re:Samsung! (Score:4, Insightful)
In summary: Your statistical analysis on a sample size of one showed a 100% failure rate, so Samsung are crap. You found some other people also had failed Samsung drives, so Samsung are crap.
Search the net and you will find people ranting about Seagate drives failures, Western Digital drive failures, IBM drive failures, Maxtor drives failures and failures of drives made by companies neither of us have even heard of. You won't find many, if any, reports of recent failures with 8" floppy drives though, so I suggest you use one of those. They must be more reliable, right?
Yes it does (Score:2)
Re:Hmm (Score:4, Interesting)
The article states that, in about half of the failures, there were no SMART warnings at all. Okay, but what was the breakdown in the kinds of failures of these unpredicted ones? If they were all spindle motor and head traversal failures, then you can't blame SMART for that. If it turns out that SMART gave warnings for 95% of all failures that were media-degradation related (like bad sectors, etc... where the drive still talks to your machine properly, and just can't get the data you want), then I'd say SMART is pretty darn useful.
But, alas, I didn't see any breakdown for failure type....
Did they ever name the brands? (Score:4, Insightful)
That would be corporate dynamite (Score:5, Insightful)
Re:That would be corporate dynamite (Score:4, Interesting)
Re:That would be corporate dynamite (Score:5, Insightful)
Re:That would be corporate dynamite (Score:2)
ps... they cost about $300 then.
And you call yourself an antique:-)
They do say that "vintage" matters (Score:5, Interesting)
Manufacturers have good years and bad years. The writers don't want to damn a company because it had a couple of bad years during this time period.
Still, it's a bummer that the single most important factor goes unpublished. Even if it could cause a panic I'm sure there's some useful information in there (eg. a company to avoid like the plague).
Re:That would be corporate dynamite (Score:4, Insightful)
Re:That would be corporate dynamite (Score:3, Insightful)
Re:That would be corporate dynamite (Score:5, Insightful)
Old Google Motto: Don't do anything evil.
New Google Motto: Don't get into trouble.
Re:That would be corporate dynamite (Score:3, Funny)
"Don't get caught doing anything evil."
You can get IDE/SATA drives FAILURE RATES Here (Score:5, Informative)
http://pro.sunrise.ru/articletext.asp?reg=30&id=2
http://pro.sunrise.ru/docs/30/image001.gif [sunrise.ru] - IDE/SATA (3.5" formfactor)
http://pro.sunrise.ru/docs/30/image002.gif [sunrise.ru] - HDD (2.5" notebook formfactor)
In short, most returns are for Maxtor brand. Lowest - IBM/Hitachi.
Toshiba is worst in 2.5", and Seagate is best.
The chance to be blown are between 1/20 (Maxtor) to 1/70 (Hitachi).
Re:That would be corporate dynamite (Score:4, Informative)
On the other hand, hard drives change so much that this year's model will be totally different design and mechanics than next years, so blaming (say) IBM for its crappy deskstar range should not be reason to blame their (ok, Hitachi's) current line.
If you do want to know more about which drives are best - check out storeagereview [storagereview.com] and enter details of your drives to their reliability database.
Re:Did they ever name the brands? (Score:5, Interesting)
breakdown of drives per manufacturer, model, or vintage
due to the proprietary nature of these data.
But, of course.
Thanks, missed that... (Score:2)
Re:Thanks, missed that... (Score:3, Insightful)
The right to stay silent on something is just as important a freedom as the right to have your say.
Censorship has nothing whatsoever to do with it.
Re:Did they ever name the brands? (Score:3, Insightful)
Re:Did they ever name the brands? (Score:4, Insightful)
Re:Did they ever name the brands? (Score:2, Interesting)
Re:Did they ever name the brands? (Score:5, Funny)
Re:Did they ever name the brands? (Score:3, Insightful)
They should have done brand analysis (without naming the brand) and also rpm analysis.
From the article..
Re:Did they ever name the brands? (Score:3, Informative)
Re:Did they ever name the brands? (Score:4, Insightful)
Very true! (Score:2)
Re:Did they ever name the brands? (Score:2)
Re:Did they ever name the brands? (Score:2, Interesting)
Or maybe the manufacturer just realized that 5 years down the road, a replacement for your then 5 year old HD will cost them peanuts. Accoring to the graph at http://en.wikipedia.org/wiki/Hard_drives#Capacity [wikipedia.org], HD capacity seems to be increasing by roughly ten times every five years.
It's like the CD-R manufacturers stamping all the packaging with 100-year guarantees. They don't really have any good way of telling that they will actually last that long, but the replacement costs nearly nothing, and thus is payed for by the marketing benefits.
Re:Did they ever name the brands? (Score:3, Insightful)
You know, I don't give a monkey's. What you lose when a disk goes down (if you haven't done your backups properly) is typically far more valuable than the disk mechanism itself. Any manufacturer can put a five-year warranty on a disk mechanism as a gimmick. Most users won't remember the warranty when the disk goes down, and, even if they have to replace 10% of the units 'free', it doesn't take much on the retail price to cover that.
20 years ago we had a spate of failures on Western Digital drives on machines which were out with customers. That really hurt - giving our customers free drives would not have cheered them up. 10 years ago we had a spate of failures of Samsung drives in a server farm. That was more under control, but it was still a bloody nuisance. I don't want a drive which fails, but when it fails I get a new one free. I want a drive that doesn't fail. The warranty has absolutely nothing to do with it.
Re:Did they ever name the brands? (Score:3, Interesting)
What? So the part about which variables are correlated with drive failures (which is what the report was about) wasn't interesting to you? Too bad.
Re:Did they ever name the brands? (Score:3, Insightful)
And thus on the third day the FSM created backups and saw it was good.
Re:Did they ever name the brands? (Score:3, Insightful)
Translation (Score:4, Funny)
Ideally, they would have formatted the text to spell out the names of the brands if you take the first letter of every Nth word, or some specific column of text. (Or maybe they have...)
Re:Translation (Score:5, Insightful)
Re:Translation (Score:5, Insightful)
Re:Translation (Score:5, Insightful)
We're not so bloody stupid to believe that our competitors are standing in the aisle of Circuit City and scratching their head over whether to buy a Seagate or WD drive.
We know that our competitors all have their own metrics and their own relationships with manufacturers and frankly, we don't care. We know our competitors also measure these things, and we're not telling them anything they don't already know.
We aren't particularly worried about saying that some drives fail, because everyone who cares already knows that some drives fail. Everyone whose job it is to know which drives fail first already knows that as well.
But we're not going to tell you which brand fails at a higher rate than normal because we don't need a lawsuit that would cost us a lot of money but in the end would only confirm what the people who need to know these things already know.
We will, on the other hand, describe the tests we ran, our methodology, our results, and our analyses. We do this just for kicks and we hope you can learn something from the results.
And we hope you have a nice day.
Re:Translation (Score:2)
It is clearly not proprietary to the drive manufacturers, because it came from Google's study. This means they regard it as proprietary to themselves.
How do you know that their competitors have done equally good studies? Given the large population (100,000) and the fact that people are surprised even by some of the published conclusions, it is very likely that there are things in there that their competitors do not know.
But we're not going to tell you which brand fails at a higher rate than normal because we don't need a lawsuit that would cost us a lot of money but in the end would only confirm what the people who need to know these things already know.
Unless they have signed some sort of NDA, agreeing not to release test results, what exactly can they be sued for? Unless you can either find evidence that buyers of hard drives sign NDAs, or specify some other grounds on which they could be sued, this sounds plain wrong to me.
Re:Translation (Score:3, Insightful)
Makes sense. Killing the weaker infants makes the adult population healthier.
Re:Translation (Score:3, Interesting)
You need backups anyway, that's not the point. But it makes a difference for your maintenance-costs if you experience 1% of your disc-drives dying in an anverage year or 5%.
Re:Translation (Score:3, Funny)
Re:Translation (Score:2)
Re:Translation (Score:2)
Sigh. That's the most misinformed post I've ever seen on Slashdot. Demand, by itself, says absolutely nothing about the price of something.
Re:Translation (Score:2)
I wish Google released the data they found because it would force the crappy drive companies to improve their products.
Re:Translation (Score:2)
Demand and price in a free market are reversely proprotional.
One way to spot someone who doesn't really understand economics is how quickly they make statements like that. You would need to know a lot more about the thing in question before being able to make a generalization like that. Sometimes, they're directly proportional, sometimes, they're reversely proportional, and sometimes they're neither. It depends on a lot of other things which relationship hold true, if any.
Re:Did they ever name the brands? (Score:5, Funny)
Re:Did they ever name the brands? (Score:2)
I think that's understandable given the litigious nature of business today...
Makes it a little less useful from a practical standpoint though...
What do you want to bet (Score:2)
Re:Did they ever name the brands? (Score:2)
Re:Did they ever name the brands? (Score:2)
However, in this paper, we do not show a
breakdown of drives per manufacturer, model, or vintage
due to the proprietary nature of these data.
and then add to it with:
Interestingly, this does not change our conclusions. In
contrast to age-related results, we note that all results
shown in the rest of the paper are not affected signifi-
cantly by the population mix.
Proprietary? Wrong use of the word there. What they really mean is we do not want to make specific companies look bad or maybe they do not want people to make incorrect conclusions based on the scope of their specific testing. In reality, I think the specific models and companies would be interesting though.
For hard drives in general, this is very interesting information. For what specific drives to avoid, this report is no useful.
Google had this paper ready a year ago (Score:3, Funny)
Conclusion (Score:4, Informative)
"In this study we report on the failure characteristics of consumer-grade disk drives. To our knowledge, the study is unprecedented in that it uses a much larger population size than has been previously reported and presents a comprehensive analysis of the correlation between failures and several parameters that are believed to affect disk lifetime. Such analysis is made possible by a new highly parallel health data collection and analysis infrastructure, and by the sheer size of our computing deployment.
One of our key findings has been the lack of a consistent pattern of higher failure rates for higher temperature drives or for those drives at higher utilization levels. Such correlations have been repeatedly highlighted by previous studies, but we are unable to confirm them by observing our population. Although our data do not allow us to conclude that there is no such correlation, it provides strong evidence to suggest that other effects may be more prominent in affecting disk drive reliability in the context of a professionally managed data center deployment.
Our results confirm the findings of previous smaller population studies that suggest that some of the SMART parameters are well-correlated with higher failure probabilities. We find, for example, that after their first scan error, drives are 39 times more likely to fail within 60 days than drives with no such errors. First errors in reallocations, offline reallocations, and probational counts are also strongly correlated to higher failure probabilities. Despite those strong correlations, we find that failure prediction models based on SMART parameters alone are likely to be severely limited in their prediction accuracy, given that a large fraction of our failed drives have shown no SMART error signals whatsoever. This result suggests that SMART models are more useful in predicting trends for large aggregate populations than for individual components. It also suggests that powerful predictive models need to make use of signals beyond those provided by SMART."
Similar paper (Score:4, Informative)
and in the meanwhile... (Score:4, Informative)
C'mon, slashdot. There were about twenty other papers presented at FAST this year. Let's not focus only on the one with Google authors...
Re:and in the meanwhile... (Score:4, Insightful)
While at a glance, it may seem like this is simply "the latest thing google did," and... let's be honest, given the editor in question... this was most likely the reason it made the front page. But while Bianca Shroeder's report, for instance, uses statistics from various unnamed sources and for various unnamed uses, the Google report is interesting because we know exactly where it's coming from and what it's being used for.
Of course, a truly insightful story would have taken this opportunity to compare Google's findings with the others and report on that.
Temperature conclusion (Score:5, Interesting)
Re:Temperature conclusion (Score:3, Insightful)
Re:Temperature conclusion (Score:4, Interesting)
While this would require a more laboratory-like environment, a dozen drives of each type and manufacture could have been sampled at known temperatures, and a data curve could have been established to calibrate the temperature sensors.
There are lots of studies out there where drives were intentionally heated, and higher degrees of failure were indeed reported (this is mentioned in the google report too). So the correlation is probably still valid, just not well-proven.
Re:Temperature conclusion (Score:3, Insightful)
This is why, if you want your engine to last, you should let your car warm up before driving it hard.
Lower temp == higher failure rates (Score:5, Interesting)
Re:Lower temp == higher failure rates (Score:2)
Re:Lower temp == higher failure rates (Score:2, Insightful)
Re:Lower temp == higher failure rates (Score:3, Insightful)
Proprietary makes sense here (Score:4, Insightful)
Litigation avoidance may be a consideration here but why not take Google at their word? Google is a search company that buys lots of hard drives. Based on their own internal research, they have developed information about which hard disk models and/or manufacturers are shite.
Yahoo is also a search company that buys lots of hard drives. Why should Google give that hard drive reliability information to you, me and Yahoo for free? Let Yahoo/Excite/MSN and the competitors figure it out for themselves.
Yeah, sure I'd like to have access to Google's data the next time I'm in the market for a hard drive but I won't hold a grudge against them if they don't do my consumer research for me. On the other hand, whereinafuck is the data from Tom's Hardware Guide, Anandtech, Consumer Reports and all the other reviewer and consumer sites? If someone doesn't have a handy link to their results, I'll see if I can google something up:
http://www.google.com/search?hl=en&safe=off&clien
This speaks volumes. (Score:5, Funny)
power supplies (Score:2)
Run smartd and look for scan errors (Score:2)
The GDRIVE (Score:2, Interesting)
I read the abstract and the conclusion (Score:2)
It's interesting, and I tend to trust their results, but these conclusions may not be relevant to single-drive situations. That is, if two customers purchase 1 drive each, and both drives are not defected, then this study doesn't explain why one drive would fail before the other. It also doesn't take into account the 1-year warranty foisted on the majority of PC-system purchasers these days.
How many drives really (Score:5, Insightful)
The paper claims "more than 100 thousand drives". But the nice thing is that you can derive the actual number from the error bars, for example those in figure 4. The data should be governed by Poisson statistics, which means that the standard deviation in the counts is equal to the square root of the count. However, their error bars seem to be about a factor 2 larger than the standard deviation, because normally around 68% of the data points should lie within one standard deviation from the "smooth curve". Let's assume the error bars are 95% confidence intervals, i.e. 2 standard deviations.
Look at the data for 20 to 21 C. It tells you that it represents a fraction 0.0135 of their total drive population, with an average failure rate of 7 +- 0.5 %. Following the reasoning above, this 7% should represent 784+-28 drives. Since these represent 7% of 1.35% of the total number of drives, we can derive that the total number of drives is 784/0.07/0.0135 = 830,000 drives. Trying the same thing for 30 to 31 C gives 826,000 drives, which seems fairly consistent.
So can we assume that Google has deployed 830,000 hard disk drives since 2001? How many servers do they have now?
Re:How many drives really (Score:3, Insightful)
Do you really think that they don't store every cookie and search pattern that everyone who uses their search engine? Cross-reference all this data, alter their ranks, follow your interests, use those to make money and target you with ads?
There is a ton of money for this information, and with enough stored data and having the facility to mine it, filter it, and sort it to location level for various advertising categories for advertisers.
Google has been very smart in the way they do business - they make money of studying your habits and selling the result (in the form of stats and/or ads).
Bell Labs (Score:3, Insightful)
Temperatures (Score:3, Interesting)
I have been previously led to believe that it's not so much the average temperature of a hard drive that causes failure, but temperature fluctuations. This makes sense, since repeated expansion and contraction of the disk platters is likely to cause warpage before too long. This, I guess, is where glass platters like what IBM toyed with would come in useful. In the meantime I guess we still need our HVAC units to keep a constant temperature, just not too low anymore.
This also has implications for data centers that spend a considerable amount of energy pumping heat out of the server room. If we can raise the undustry-accepted temperature ceiling from 22C to say 30C then a lot of energy can be saved over time. Perhaps not quite enough to dip below 1% of US-wide power use but every bit helps.
Re:Temperatures (Score:3, Informative)
I think you are partly right in this assumption, but for the wrong reasons. Some failure modes are a function of temperature and other failure modes are a function of temperature variation. A long time ago platter expansion and contraction was a major cause of problems when drives used stepper motor positioning; since they switched to servo positioning, the drive automatically tracks the expansion and contraction of the platters and that is pretty much a non-issue as long as the coating on the platters is not affected.
This report reads like it was done by statisticians, not engineers. Handling of temperature, in particular, reveals this. As someone who has designed electronic circuits, been involved in reliability analysis, and repaired broken computers and other equipment at both the board level and chip level, I get the impression that the writers have not done any of those things.
Also, the conditions in google RAID arrays are likely very different than may be encountered in many other areas such as office and desktop PCs. In the raid arrays drives are not powered down daily and you also expect better cooling design.
The higher failure of lower average temperature drives is a definite eyebrow raiser. Not because it disproves the common wisdom (which still applies in the expected range) but because it is probably the clue that some important data was overlooked. If you actually extrapolate the right side of the graph, you see that failure does increase dramatically with temperature over the range of temperatures that would be experienced in normal cooling situations and particularly cooling failures.
Google has drives that are running at room temperature? This could point to some serious temperature fluctuation, measurement error, or to extremely aggressive cooling local cooling (chilled water or freon A/C) or a server room that is chilled like a walk in freezer. In which case, those drive failures are probably caused by moisture. At normal operating temperatures, a drive will drive off moisture. At the cooler temperatures, there may be condensation issues on the drive itself or on cooling components near the drive.
The reason that we don't see high temperature rate failures is that the sample of temperatures is abnormally low. The most common temperature related failures would be when you have a cooling failure or poor cooling. Good cooling does improve the lifetime of the drive. That does not mean, however, that cooling to extremes is a good idea. In a typical PC, the drive is going to run at somewhere around 40 degrees C. The drive on this computer, right now, which is mounted in a typical mid tower case in a slightly chilly room (it is winter here) that would be a lot more chilly without three computers heating it, is running at 39degrees. That temperature corresponds to the crest of the failure vs. temperature curve on googles graphs. What temperature do you think drive manufacturers would optimize their designs for? A typical commercial grade chip is rated 0 to 70 degrees C so the thresholds would be expected to be optimized for 35 degrees C. Drive manufacturers would expect the normal operating temperature to be around 40 degrees C. The paper says they use consumer grade drives. The datasheet for a WD 250GB hard drive [zdnet.com] says the minimum operating (ambient, not drive temperature) is 5 degrees C (41F) to 55 degrees C (131F). I noticed in doing a google search that some drives specified a minimum storage temperature of -13C.
Also, if the average temperature is low, that may be an indication that the drives in that particular population are drives that are spun down or even powered down much of the time, perhaps because the particular datasets they are serving are infrequently used or because they data is entirely cached in RAM.
Also, they talked about average temperature over the life
One of TWO best papers at FAST (Score:3, Informative)
You might be interested in the other best paper award winner (in the shameless self-promotion department): TFS: A Transparent File System for Contributory Storage [usenix.org], by Jim Cipar [umass.edu], Mark Corner [umass.edu], and Emery Berger [slashdot.org] (Dept. of Computer Science, University of Massachusetts Amherst [umass.edu]). Briefly, it describes how you can make all the empty space on your disk available for others to use, without affecting your own use of the disk (no performance impact, and you can still use the space if you need it).
Enjoy!
--
Emery Berger
Dept. of Computer Science
University of Massachusetts Amherst
Re:So (Score:2)
Re:So (Score:2)
Re:So (Score:2, Informative)
From my experience, Western Digitals are (relatively) reliable. They unfortunately do not have the same power connector orientation as any other consumer drive on the planet, so if you want to use IDE RAID you have to get the type that either (1) fits any consumer ide drive or (2) fits a Western Digital Drive. (grr)
Had some good experiences with Maxtor. A couple of years ago (OK - maybe 6 or 8) we had batches of super reliable Maxtors - 10GB.
Some Samsungs are good, some are evil - the SP0411N was a particularly reliable model - the SP0802N sucked - out of a batch of 20, 15 of them died within a year: all reallocated sector errors beyond the threshold.
Seagates are a mixed bag too - been having a nice experience with the SATA models 160GB and 120GB - can't remember their model #'s off the top of my head. - The older Seagates, though, I spent a fair amount of time replacing.
IBM DeskStar's, as far as I know, have been quite good - for some reason didn't use too many.
Re:So (Score:2, Informative)
The DeskStars were nicknamed DeathStars due to their high failure rate.
Maxtor has a terrible reputation in the channel.
Seagate has a fantastic reputation in the channel.
And as far as the WD power connectors.. I have 4 Western Digitals, a Samsung, a Maxtor, and a Seagate on my desk right now.. and they all have the same layout (left to right: 40 pin, jumpers, molex).
Re:So (Score:2)
Seagate also does NOT offer advance drive replacement in Canada, which means I'll never buy another of their products until this policy changes.
Had good luck with more recent Western Digital drives. Put 5 x 500GB in a RAID-5 server, and they're running great!
N.
Re:OS X SMART tool? (Score:4, Informative)
Not exactly point & click but it'll do.
Re:OS X SMART tool? (Score:3, Informative)
I had a disk reporting a SMART failure once. The result was that the disk was red in the list in Disk Utility, but there were no other warnings. So you might want to check Disk Utility once in a while.
Re:I'm obviously behind the times, but... (Score:2, Informative)