ZFS Data missing in a degraded zfs pool

Hi !

This is my first experience with ZFS.

I have created a raidz2 zfs pool with 5 drives, no spares (I know won't happen again). It's a lab server so no critical data.
The pool became degraded after a HD failure. (showing as FAULTED with too many errors).

Result:
  • Some of data I had previously disappeared

I was wondering if:
  • the data should still be available in a degraded mode?
  • If I replace the faulty drive, will it be possible to recover the lost data?

Thanks !
 
I don’t really see running raidz2 without spares as a massive issue. I run several similar systems with no spare. Part of the benefit of raidz2 is that it I still get redundancy after a failure while I sort out a replacement for the failed disk.

If a single drive has failed but the pool is only degraded I wouldn’t expect to see missing data. What does zpool status look like?
 
In addition to usdmatt's question: What do you mean by "disappeared"? What exactly happens when you try to access or read the data? What shows up in the system log?
 
I don’t really see running raidz2 without spares as a massive issue. I run several similar systems with no spare. Part of the benefit of raidz2 is that it I still get redundancy after a failure while I sort out a replacement for the failed disk.

If a single drive has failed but the pool is only degraded I wouldn’t expect to see missing data. What does zpool status look like?
Code:
state: DEGRADED
status: One or more devices are faulted in response to persistent errors.
        Sufficient replicas exist for the pool to continue functioning in a
        degraded state.
action: Replace the faulted device, or use 'zpool clear' to mark the device
        repaired.

NAME                                          STATE     READ WRITE CKSUM
        storage                                       DEGRADED     0     0     0
          raidz2-0                                    DEGRADED     0     0     0
            ata-1                 ONLINE       0     0     0
            ata-2  ONLINE       0     0     0
            ata-3  ONLINE       0     0     0
            ata-4  ONLINE       0     0     0
            ata-5  FAULTED      0     0     1  too many errors

errors: No known data errors
 
In addition to usdmatt's question: What do you mean by "disappeared"? What exactly happens when you try to access or read the data? What shows up in the system log?

I had a NFS setup to share over the network. One of the shares was intended to host iso's.
example when a do 'zfs list', I can see only a 300MB file I've added recently under that directory.
All the previous iso's are gone ( but somehow it says that 3,21GB is used)

storage/share/iso 3.21G 2.19T 3.21G /storage/share/iso
 
I had a NFS setup to share over the network. One of the shares was intended to host iso's.
example when a do 'zfs list', I can see only a 300MB file I've added recently under that directory.
All the previous iso's are gone ( but somehow it says that 3,21GB is used)
I'm betting you've mounted something on top of it. The data is there just "masked" by the extra mount.
 
Yes, either that or the ZFS dataset isn't actually mounted at all.

The pool has 0 errors and should be perfectly intact.
somehow the dataset wasn't mounted anymore.
by mounting manually using 'zfs mount -a -O' the data appeared again yaay !!!!.
but I still don't understand why it did happen.
 
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