Re: [zfs-discuss] FS Reliability WAS: about btrfs and zfs
On Sat, Oct 22, 2011 at 11:36 AM, Paul Kraus p...@kraus-haus.org wrote: Recently someone posted to this list of that _exact_ situation, they loaded an OS to a pair of drives while a pair of different drives containing an OS were still attached. The zpool on the first pair ended up not being able to be imported, and were corrupted. I can post more info when I am back in the office on Monday. That is nasty :P I wonder if Darik's approach for zfsonlinux is better. In Ubuntu's (currently unofficial) zfs root support, the startup script force-imports rpool (or whatever pool the user specifies on kernel command line, if explicitly specified), and drops to a rescue shell if there are more than one pool with the same name. This means: - no problem with pools previously imported in another system - no corruption due to duplicate pool name, as when that happens the user needs to manually take action to import the correct pool by id - the other pool remains untouched, and (if necessary) the user can reimport it under different name -- Fajar On Friday, October 21, 2011, Fred Liu fred_...@issi.com wrote: 3. Do NOT let a system see drives with more than one OS zpool at the same time (I know you _can_ do this safely, but I have seen too many horror stories on this list that I just avoid it). Can you elaborate #3? In what situation will it happen? Thanks. Fred ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] File contents changed with no ZFS error
I've noticed something strange over the past few months with four files on my raidz. Here's the setup: OpenSolaris snv_111b ZFS Pool version 14 AMD-based server with ECC RAM. 5 ST3500630AS 500 GB SATA drives (4 active plus spare) in raidz1 The other day, I observed what appears to be undetected file corruption in 4 of the files on the raidz. I have two external USB hard drives that I use to back up the contents of the ZFS raidz on alternating months. The USB hard drives use EXT3 so they are connected to a Linux box which in turn connects to the raidz over NFS. Occasionally, I use the checksum option on rsync (rsync -ainc) to make sure everything on the USB hard drives match before I perform the real rsync back from the raid to the USB disk and that's when I noticed the changes. In each file, there was a single byte changed. Running zpool status doesn't show any errors and running zpool scrub doesn't show any problems either. One of the changed files was a .ppt file that I downloaded from the web over a year ago and the other 3 were Acronis incremental Backup files from my XP machine that get stored on the raidz. Since ZFS files aren't supposed to be corrupted without notification (right?), I initially assumed the problem was with the USB drive. For the 3 Acronis backup files, I had no way of knowing which version was the correct one because Acronis shows all of them to be valid. The .ppt file was not on the web anymore but with the help of the Wayback machine, I was able to re-download it and that's when I confirmed the good copy from the web matches the copy on my USB hard drive, not the copy on the raidz. I know I haven't modified the .ppt file because the date still matches the date I downloaded it, 2010-01-12. What failure scenario could have caused this? The file was obviously initially good on the raidz because it got backed up to the USB drive and that matches the good version from the web. Thanks in advance, -Bob ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] File contents changed with no ZFS error
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Robert Watzlavick What failure scenario could have caused this? The file was obviously initially good on the raidz because it got backed up to the USB drive and that matches the good version from the web. How can you outrule the possibility of something changed the file. Intentionally, not as a form of filesystem corruption. If you have snapshots on your ZFS filesystem, you can use zhist (or whatever technique you want) to see in which snapshot(s) it changed, and find all the unique versions of it. 'Course that will only give you any valuable information if you have different versions of the file in different snapshots. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] File contents changed with no ZFS error
On Oct 22, 2011, at 13:14, Edward Ned Harvey opensolarisisdeadlongliveopensola...@nedharvey.com wrote: How can you outrule the possibility of something changed the file. Intentionally, not as a form of filesystem corruption. I suppose that's possible but seems unlikely. One byte on a file changed on the disk with no corresponding change in the mod time seems unlikely. I did access that file for read sometime I'm the past few months but again, if it had accidentally been written to, the time would have been updated. If you have snapshots on your ZFS filesystem, you can use zhist (or whatever technique you want) to see in which snapshot(s) it changed, and find all the unique versions of it. 'Course that will only give you any valuable information if you have different versions of the file in different snapshots. I only have one or two snapshots but I'll look. Thanks, -Bob ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] File contents changed with no ZFS error
On Oct 22, 2011, at 12:55, Garrett D'Amore garrett.dam...@nexenta.com wrote: You're using an *old* version of both OpenSolaris and zpool. There have been a few corruption bugs fixed since then. I'd recommend updating. - Garrett I was looking for the changelist to see if any have been fixed but couldnt find it. This is 2009.06 with some updates but not the final set. It's just a fileserver so I was tempted to freeze the config since it's not on the net and it has been working so well (then again maybe not). Do you know if the final updates to 2009.06 can still be applied? -Bob On Oct 22, 2011, at 9:27 AM, Robert Watzlavick wrote: I've noticed something strange over the past few months with four files on my raidz. Here's the setup: OpenSolaris snv_111b ZFS Pool version 14 AMD-based server with ECC RAM. 5 ST3500630AS 500 GB SATA drives (4 active plus spare) in raidz1 The other day, I observed what appears to be undetected file corruption in 4 of the files on the raidz. I have two external USB hard drives that I use to back up the contents of the ZFS raidz on alternating months. The USB hard drives use EXT3 so they are connected to a Linux box which in turn connects to the raidz over NFS. Occasionally, I use the checksum option on rsync (rsync -ainc) to make sure everything on the USB hard drives match before I perform the real rsync back from the raid to the USB disk and that's when I noticed the changes. In each file, there was a single byte changed. Running zpool status doesn't show any errors and running zpool scrub doesn't show any problems either. One of the changed files was a .ppt file that I downloaded from the web over a year ago and the other 3 were Acronis incremental Backup files from my XP machine that get stored on the raidz. Since ZFS files aren't supposed to be corrupted without notification (right?), I initially assumed the problem was with the USB drive. For the 3 Acronis backup files, I had no way of knowing which version was the correct one because Acronis shows all of them to be valid. The .ppt file was not on the web anymore but with the help of the Wayback machine, I was able to re-download it and that's when I confirmed the good copy from the web matches the copy on my USB hard drive, not the copy on the raidz. I know I haven't modified the .ppt file because the date still matches the date I downloaded it, 2010-01-12. What failure scenario could have caused this? The file was obviously initially good on the raidz because it got backed up to the USB drive and that matches the good version from the web. Thanks in advance, -Bob ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] File contents changed with no ZFS error
Why don't you see which byte differs, and how it does? Maybe that would suggest the failure mode. Is it the same byte data in all affected files, for instance? Mark Sent from my iPhone On Oct 22, 2011, at 2:08 PM, Robert Watzlavick rob...@watzlavick.com wrote: On Oct 22, 2011, at 13:14, Edward Ned Harvey opensolarisisdeadlongliveopensola...@nedharvey.com wrote: How can you outrule the possibility of something changed the file. Intentionally, not as a form of filesystem corruption. I suppose that's possible but seems unlikely. One byte on a file changed on the disk with no corresponding change in the mod time seems unlikely. I did access that file for read sometime I'm the past few months but again, if it had accidentally been written to, the time would have been updated. If you have snapshots on your ZFS filesystem, you can use zhist (or whatever technique you want) to see in which snapshot(s) it changed, and find all the unique versions of it. 'Course that will only give you any valuable information if you have different versions of the file in different snapshots. I only have one or two snapshots but I'll look. Thanks, -Bob ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
