You don't even need a raid to be able to do that test.. EDIT2: I apologies for the wording with 'lies' and 'bullshit'. So it should be pretty simple to write a pattern to a disk and then read it back 4 times and you get your URE. If either the write or the re-read fail, md will treat the error the same way that a write error is treated, and will fail the whole device."----Below are a couple navigate here
What I'm not OK with is that people read these spec sheets and then claim RAID5 is dead and scare everybody with this. But very small for home usage. Solaris code is available for partners and licensees through the Oracle Technology Network (OTN). d_handling"Modern drives make extensive use of error correction codes (ECCs), particularly Reed–Solomon error correction.
Or does it take a little while for Oracle to let others play with it? So I suspect that overall consumer drives are way more reliable than their spec and that the risks of UREs are not as high as people may think. That level of insufficient protection is present when rebuilding any RAID 5 array, regardless of whether the server is using Linux software RAID, a Dell Perc H710p hardware RAID controller with Yes, it really does happen, and more often than you think.
So what I observe on many of these drives is a steady degradation of IOPS capability as they begin to use up spare sector pool over the years (which is, in Disclaimer: I am an Oracle employee. Oracle is, as such, emphatically not the upstream of ZFS; they are a fork, for which source code is not (and likely never will be) available. Hard Drive Ure Often, those reasons have more to do with people's behaviour than with the bits and bytes.
Those don't even get replaced. Doing statistical calculations with better records could allow the cause of that to be identified. ChuckMcM 764 days ago And to be clear, it is a bit error rate not That means that there is a chance that you get a read error every 12.5 TB of data. I can't imagine this is really normal.
permalinkembedsavegive gold[–]FunnySheep[S] 0 points1 point2 points 1 year ago(8 children)Thanks for this info. Zfs Ure That said, RAID5 or RAIDZ is still perfectly fine as long as you don't put too many drives in an array. permalinkembedsaveparentgive gold[–]FunnySheep[S] 0 points1 point2 points 1 year ago(1 child)I agree with architechnology, that's an interesting read. but even then, it's not a guarantee.
Don't try to champion single parity for home hobbyists. A single disk has ZERO redundancy and so it can't simply calculate the missing bit of data from a URE. Raid 5 Ure Calculator Sure, you can move to better enterprise drives if you want to minimize the chances of loosing a file or block of files effected by the loss of that sector, but Raid 10 Ure You'd need to check your logs (on Solaris-based systems, "fmdump -e" to show the fault management private log will do this) to evaluate whether you're seeing SCSI resets or not.
You also get UREs for very weird reasons. check over here Especially for smaller arrays. YMMV. e.g. What Happens If The Array Experiences A Ure During The Rebuild Process?
Because I've never read it interpreted it that way. Unfortunately, due to drive vendor agreements, I'm not free to share that data. Related Point: "Enterprise" 10,000 - 15,000 RPM drives often show much better reliability statistics over time in large part because they are short-stroked from the factory. his comment is here YOU CANNOT ADD STATISTICS TOGETHER!Stop worrying about someone's misunderstanding of simple mathematics and just start using the devices that you have.
To be fair, if you're using enterprise drives, you're much more likely to have a drive die cleanly rather than read or write bad data... Raid 6 Ure Oracle contributes code to many open-source and free software projects. This has often taken me into ridiculous-land with stripe widths in excess of 34 drives (32 drives + 2 parity) where the minimum blocksize is equal to or larger than the
permalinkembedsaveparentgive gold[–]FunnySheep[S] 0 points1 point2 points 1 year ago(0 children)Ok thanks for the information, that's interesting. And if you're doing THAT, well, you DEFINITELY shouldn't be using RAIDZ1 - particularly given that (again, overwhelmingly in hobbyist use) there's probably no backup and therefore pool failure doesn't mean Modern drives position the read head right "behind" the write head in order of rotation and read the data on the same pass as the write. Disk Ure It may even help you survive if you encounter an URE with 2 drives lost in a RAIDZ2.
Regardless of doing any rebuild you are going to see a read error that will not be detected by the RAID as every read of data that you take off the So thanks for that. I'm running a RAID6 of 18 drives and a RAID6 of 6 drives in a single pool for a year or more and can confirm that ZoL nicely balances everything over weblink One explanation is that the scrubs don't touch the whole surface of the drives, but that's offset with the fact that I use 24 different drives, so I throw with 24
permalinkembedsaveparentgive gold[–]architechnology 0 points1 point2 points 1 year ago(25 children)Apologies for replying to myself, just in case you haven't seen it, Backblaze publishes some great real-life reliability stats https://www.backblaze.com/blog/best-hard-drive/ permalinkembedsaveparentgive gold[–]FunnySheep[S] 0 points1 point2 Is any of you aware of any real-world test URE numbers of disks in the field? RAIDz2: Three drive failures in "degraded" mode (you've lost both parity disks) RAIDz3: Dear god why? RAID5 must only be applied with some wisdom only for small arrays or VDEVs.
Here is the equation:(1 - (99,999,999,999,999 / 100,000,000,000,000) ^ 48,000,000,000,000) = 0.380979164As you stated, drives are read a sector at a time, not a bit at a time. Kinda' like Y2K fifteen years ago, really. Software defects. permalinkembedsaveparentgive gold[–]m1ss1ontomars2k4 1 point2 points3 points 1 year ago(0 children) Because I've never read it interpreted it that way.
Stripe: No drive failures tolerated. permalinkembedsaveparentgive gold[–]SirMaster 0 points1 point2 points 1 year ago*(15 children) Assuming two vdevs in a pool, if one is half the size of the other it will receive only one-third of the writes. Correct. I'd clarify that in practical use, URE don't really seem to change, decrease, or increase over a drive's lifetime (in aggregate, large numbers).
Any checksum error is bad data returned from a drive, period. Since 1982, MTR has produced the industry’s most in-depth, accurate, and effective seminars, books, articles, videos, and FAQs covering PC hardware and data recovery. At the point your drives have deteriorated to the point you get your first URE, what is then the probability that you will get further UREs within the rebuild period? If the user never scrubs their pools, alarmism about their data security is entirely appropriate.
You might want to look at that statistic more as a measure of how well the drive manages bit rots (that is the eventual decay of magnetism that controls whether a I suggest avoiding RAID 5 when the total array size will be larger than roughly 2TB, maybe less than that.