zpool import/export

[afreedma]

Hi all,

I originally put together a RAID-Z1 setup under FreeNAS 0.7.2, consisting of 6 2Tb drives and a 256Gb SSD cache I had gathering dust. Since then I've migrated to FreeNAS 8.0-RELEASE and was able to kinda/sorta import the filesystem to a workable degree.

Since then, I've had a drive fail, which I replaced today. In the process, the cache drive has started reporting "corrupted data". That doesn't seem too alarming; once the resilvering is complete I'll zpool remove then zpool add the cache back.

The next challenge will be upgrading to 8.0.2-RELEASE, which is compounded by the fact that my system drive is a 1Gb USB header SSD (Z-U130 style). Of course, I also don't have an optical drive on this box. Awesome.

I've ordered a new USB drive and am now ruminating on the best way forward. As per the install instructions, I'm thinking I can backup my configuration, install onto the new system drive, restore the configuration and be done.

But the cruft is niggling at me… I worry that the FreeNAS db is not perfectly aligned with the OS underneath at this point.

Can anyone advise what benefits (or problems) I might accrue by issuing a zpool export, installing the new OS then running zpool import (i.e., not bother restoring the configuration backup)? Will 8.0.2 correctly grok the filesystems and give me a clean base to build from? Does the UI expose the ZFS import functionality? The remaining configuration options I can recreate in an afternoon; the crucial part is not losing any data.

Thanks,

Andrew

 

[ProtoSD]

Hi Andrew,

I've ordered a new USB drive and am now ruminating on the best way forward. As per the install instructions, I'm thinking I can backup my configuration, install onto the new system drive, restore the configuration and be done.

You should backup your configuration settings, but don't install the new version and then import your settings. I've run into problems doing this and per the release notes, you are better off to boot & upgrade from the CD which will recognize your existing installation and upgrade the database.

As far as exporting your pool prior to upgrading and importing after, you shouldn't have any problems

Will 8.0.2 correctly grok the filesystems and give me a clean base to build from? Does the UI expose the ZFS import functionality?

The answer to both of these questions is yes. One thing to keep in mind is that if the GUI doesn't expose a feature of ZFS that you want to use, export your pool, do those tasks at the command line, and then Auto Import from the GUI again. The GUI database tends to get out of sync with very little effort. You seem to be aware of the issues you need to look out for, I think you should be fine.

 

[afreedma]

Thanks - that's reassuring. Now, to hijack my own thread, resilvering has concluded:

Code:

loki# zpool status storage
  pool: storage
 state: DEGRADED
 scrub: resilver completed after 0h0m with 0 errors on Wed Oct 26 21:49:54 2011
config:

	NAME           STATE     READ WRITE CKSUM
	storage        DEGRADED     0     0     0
	  raidz1       DEGRADED     0     0     0
	    da2        ONLINE       0     0     0
	    replacing  DEGRADED     0     0     0
	      da0/old  OFFLINE      0     0     0
	      da0      ONLINE       0     0     0
	    da1        ONLINE       0     0     0
	    da3        ONLINE       0     0     0
	    da4        ONLINE       0     0     0
	    da5        ONLINE       0     0     0
	cache
	  da2          ONLINE       0     0     0

errors: No known data errors

Can't do zpool remove da0/old, while zpool export storage && spool import storage changes nothing, zpool scrub storage changes nothing and zpool clear storage also does nothing. I'm running out of ideas...

Before the export/import shuffle, status showed:

Code:

scrub: resilver completed after 2h15m with 0 errors on Wed Oct 26 19:34:48 2011

So that part seems benign at least.