Discussion:
recovering deleted files from ZFS?
(too old to reply)
CJ Keist
2016-03-14 17:41:38 UTC
Permalink
All,
Thought I try asking this question on this forum. In light of no
snapshots, is there a way in ZFS to recover a recently deleted file? We
do nightly backups, but this would be a file that was deleted before the
coming daily backup. Does anyone know if there is a service that can do
file recoveries from ZFS?
--
C. J. Keist Email: ***@colostate.edu
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301

All I want is a chance to prove 'Money can't buy happiness'
Linda Kateley
2016-03-14 17:47:14 UTC
Permalink
drive savers do some recovery.

linda
Post by CJ Keist
All,
Thought I try asking this question on this forum. In light of no
snapshots, is there a way in ZFS to recover a recently deleted file?
We do nightly backups, but this would be a file that was deleted
before the coming daily backup. Does anyone know if there is a
service that can do file recoveries from ZFS?
Bob Friesenhahn
2016-03-14 18:12:13 UTC
Permalink
Post by CJ Keist
All,
Thought I try asking this question on this forum. In light of no
snapshots, is there a way in ZFS to recover a recently deleted file? We do
nightly backups, but this would be a file that was deleted before the coming
daily backup. Does anyone know if there is a service that can do file
recoveries from ZFS?
Hopefully this is not for a problem which has already occured. A
solution would be to do zfs filesystem snapshots whenever important
data has changed or at a high enough frequency that the probability of
loss before backup is marginalized. Otherwise there is no assurance
that the deleted data remains.

Bob
--
Bob Friesenhahn
***@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
Dan McDonald
2016-03-14 18:28:46 UTC
Permalink
The very long-shot chance is to export the pool (after backing it recent changes), use zdb to see what its current TXG number is, and re-import the pool with an earlier TXG number using -T. You'll lose files or changes created after the old TXG, AND if it's been a long enough time or a full enough pool, you won't get back to that TXG.

It's an extraordinary measure, one I wouldn't take unless I was truly desperate.

Dan

Sent from my iPhone (typos, autocorrect, and all)
All,
Thought I try asking this question on this forum. In light of no snapshots, is there a way in ZFS to recover a recently deleted file? We do nightly backups, but this would be a file that was deleted before the coming daily backup. Does anyone know if there is a service that can do file recoveries from ZFS?
--
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301
All I want is a chance to prove 'Money can't buy happiness'
_______________________________________________
OmniOS-discuss mailing list
http://lists.omniti.com/mailman/listinfo/omnios-discuss
CJ Keist
2016-03-14 18:37:44 UTC
Permalink
Thank you!. In this case I think I can do this as the server is
basically retired now.
Post by Dan McDonald
The very long-shot chance is to export the pool (after backing it recent changes), use zdb to see what its current TXG number is, and re-import the pool with an earlier TXG number using -T. You'll lose files or changes created after the old TXG, AND if it's been a long enough time or a full enough pool, you won't get back to that TXG.
It's an extraordinary measure, one I wouldn't take unless I was truly desperate.
Dan
Sent from my iPhone (typos, autocorrect, and all)
All,
Thought I try asking this question on this forum. In light of no snapshots, is there a way in ZFS to recover a recently deleted file? We do nightly backups, but this would be a file that was deleted before the coming daily backup. Does anyone know if there is a service that can do file recoveries from ZFS?
--
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301
All I want is a chance to prove 'Money can't buy happiness'
_______________________________________________
OmniOS-discuss mailing list
http://lists.omniti.com/mailman/listinfo/omnios-discuss
--
C. J. Keist Email: ***@colostate.edu
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301

All I want is a chance to prove 'Money can't buy happiness'
Bob Friesenhahn
2016-03-14 18:45:37 UTC
Permalink
Thank you!. In this case I think I can do this as the server is basically
retired now.
Take care since this would toast the disks for any other recovery
attempt. The data may very well be available, especially if the file
is small (since zfs typically writes 128k at a time). Recovery is
easiest if the pool was a single disk or mirrored rather than raidzN.

There are only something like 20 transaction groups available to go
back to and this might span only a few seconds to a 100 seconds worth
of time. If the file was destroyed long before the problem was
noticed, then this approach won't work.

Bob
--
Bob Friesenhahn
***@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
CJ Keist
2016-03-14 19:13:32 UTC
Permalink
Thanks. Sounds like it's already too late then. It has been about day
and half since the deletion occurred.
Post by Bob Friesenhahn
Post by CJ Keist
Thank you!. In this case I think I can do this as the server is
basically retired now.
Take care since this would toast the disks for any other recovery
attempt. The data may very well be available, especially if the file
is small (since zfs typically writes 128k at a time). Recovery is
easiest if the pool was a single disk or mirrored rather than raidzN.
There are only something like 20 transaction groups available to go
back to and this might span only a few seconds to a 100 seconds worth
of time. If the file was destroyed long before the problem was
noticed, then this approach won't work.
Bob
--
C. J. Keist Email: ***@colostate.edu
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301

All I want is a chance to prove 'Money can't buy happiness'
CJ Keist
2016-03-14 18:42:06 UTC
Permalink
Dan,
You know if this is a just one shot attempt? Meaning if I choose
the wrong TXG to import, can I export and try again with a different TXG?
Post by Dan McDonald
The very long-shot chance is to export the pool (after backing it recent changes), use zdb to see what its current TXG number is, and re-import the pool with an earlier TXG number using -T. You'll lose files or changes created after the old TXG, AND if it's been a long enough time or a full enough pool, you won't get back to that TXG.
It's an extraordinary measure, one I wouldn't take unless I was truly desperate.
Dan
Sent from my iPhone (typos, autocorrect, and all)
All,
Thought I try asking this question on this forum. In light of no snapshots, is there a way in ZFS to recover a recently deleted file? We do nightly backups, but this would be a file that was deleted before the coming daily backup. Does anyone know if there is a service that can do file recoveries from ZFS?
--
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301
All I want is a chance to prove 'Money can't buy happiness'
_______________________________________________
OmniOS-discuss mailing list
http://lists.omniti.com/mailman/listinfo/omnios-discuss
--
C. J. Keist Email: ***@colostate.edu
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301

All I want is a chance to prove 'Money can't buy happiness'
Dan McDonald
2016-03-14 18:53:36 UTC
Permalink
Dan,
You know if this is a just one shot attempt? Meaning if I choose the wrong TXG to import, can I export and try again with a different TXG?
Import it read-only and you can probably attempt multiple TXGs.

Dan
Richard Elling
2016-03-14 19:04:23 UTC
Permalink
Dan,
You know if this is a just one shot attempt? Meaning if I choose the wrong TXG to import, can I export and try again with a different TXG?
pro tip: try retro import with readonly option


-- richard
Post by Dan McDonald
The very long-shot chance is to export the pool (after backing it recent changes), use zdb to see what its current TXG number is, and re-import the pool with an earlier TXG number using -T. You'll lose files or changes created after the old TXG, AND if it's been a long enough time or a full enough pool, you won't get back to that TXG.
It's an extraordinary measure, one I wouldn't take unless I was truly desperate.
Dan
Sent from my iPhone (typos, autocorrect, and all)
All,
Thought I try asking this question on this forum. In light of no snapshots, is there a way in ZFS to recover a recently deleted file? We do nightly backups, but this would be a file that was deleted before the coming daily backup. Does anyone know if there is a service that can do file recoveries from ZFS?
--
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301
All I want is a chance to prove 'Money can't buy happiness'
_______________________________________________
OmniOS-discuss mailing list
http://lists.omniti.com/mailman/listinfo/omnios-discuss
--
Systems Group Manager Solaris 10 OS (SAI)
Engineering Network Services Phone: 970-491-0630
College of Engineering, CSU Fax: 970-491-5569
Ft. Collins, CO 80523-1301
All I want is a chance to prove 'Money can't buy happiness'
_______________________________________________
OmniOS-discuss mailing list
http://lists.omniti.com/mailman/listinfo/omnios-discuss
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