Re: Does a failed separate ZIL disk mean the entire zpool is lost?
Date: Tue, 10 Sep 2024 10:35:25 UTC
Thank you but I'm afraid I didn't use two mirrored ZIL devices since I didn't know this was possible at the time I set this server up (late 2017 and before I was even aware of the 'FreeBSD Mastery: ZFS' book!) And there were no spare disk bays in the server's chassis to add another device and at the time PCIe > nvme adapters were not available. For data resilience I relied on an identical mirror server in the same rack linked via a 2 x 10GBit/sec bonded point-to-point network link but this server also failed in the data centre melt-down... It looks like the data is now lost so I won't waste any more time trying to recover it - this incident will hopefully persuade my employer to heed advice given years ago regarding locating mirror servers in a different data centre linked by a fast multi-gigabit connection. Andy PS: the ZFS and Advanced ZFS books are truly excellent, by the way! On Mon, 9 Sep 2024, Allan Jude wrote: > As the last person mentioned, you should be able to import with the -m flag, > and only lose about 5 seconds worth of writes. > > The pool is already partially imported at boot by the other mechanisms, you > might need to disable that to prevent the partial import at boot, so you can > do the manual import. > > On 2024-09-09 12:20 p.m., infoomatic wrote: >> did you use two mirrored ZIL devices? >> >> You can "zpool import -m", but you will probably be confronted with some >> errors - you will probably lose the data the ZIL has not committed, but >> most of your data in your pool should be there >> >> >> On 09.09.24 17:51, andy thomas wrote: >>> A server I look after had a 65TB ZFS RAIDz1 pool with 8 x 8TB hard disks >>> plus one hot spare and separate ZFS intent log (ZIL) and L2ARC cache >>> disks that used a pair of 256GB SSDs. This ran really well for 6 years >>> until 2 weeks ago, when the main cooling system in the data centre where >>> it was installed failed and the backup cooling system failed to start up. >>> >>> The upshot was the ZIL SSD went short-circuit across its power >>> connector, shorting out the server's PSUs and shutting down the server. >>> After replacing the failed SSD and verifying all the spinning hard disks >>> and the cache SSD are undamaged, attempts to import the pool fail with >>> the following message: >>> >>> NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP >>> HEALTH ALTROOT >>> clustor2 - - - - - - - - >>> UNAVAIL - >>> >>> Does this mean the pool's contents are now lost and unrecoverable? >>> >>> Andy >>> >> > > ---------------------------- Andy Thomas, Time Domain Systems Tel: +44 (0)7866 556626 http://www.time-domain.co.uk