# ZFS Resilvering: Is it incremental?



## mstrofbass (Mar 3, 2013)

So, long story short, I have one drive in my ZFS raidz pool die. Upon replacing it and trying to resilver, I have discovered that a second drive is on its way out. The second drive decides to randomly stop responding, sometimes after a few minutes, sometimes after three hours. However, it will never stay online long enough to complete resilvering, which, if it did, would be enough to complete replacement of the first dead drive. Then, I can replace the second, and hopefully save most, if not all of my data (beyond any data lost due to the drive issues).

So, the question is this: if I continue to resilver the drives, even though it fails before completion, will it eventually complete the resilvering process? Or must the process run through completion without failing?


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## HarryE (Mar 3, 2013)

I would zfs send/receive the pool on some external support, just in case... Then resilvering.
It's not so stressful on HDDs, you may be able to rescue the data on your pool.
Or stop the system and make a disk image (using dd ) of the second problematic disk on another spare drive. Then use the pool in read-only mode for backup purposes.
You cannot afford to lose the second drive!
I don't think resilvering is incremental between reboots! But I'm no expert.


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