On Mon, 11 Jan 2010, Eric Schrock wrote: > No, there is no way to tell if a pool has DTL (dirty time log) entries.
Hmm, I hadn't heard that term before, but based on a quick search I take it that's the list of data in the pool that is not fully redundant? So if a 2-way mirror vdev lost a half, everything written after the loss would be on the DTL, and if the same device came back, recovery would entail just running through the DTL and writing out what it missed? Although presumably if the failed device was replaced with another device entirely all of the data would need to be written out. I'm not quite sure that answered my question. My original question was, for example, given a 2-way mirror, one half fails. There is a hot spare available, which is pulled in, and while the pool isn't optimal, it does have the same number of devices that it's supposed to. On the other hand, the same mirror loses a device, there's no hot spare, and the pool is short one device. My understanding is that in both scenarios the pool status would be "DEGRADED", but it seems there's an important difference. In the first case, another device could fail, and the pool would still be ok. In the second, another device failing would result in complete loss of data. While you can tell the difference between these two different states by looking at the detailed output and seeing if a hot spare is in use, I was just saying that it would be nice for the short status to have some distinction between "device failed, hot spare in use" and "device failed, keep fingers crossed" ;). Back to your answer, if the existance of DTL entries means the pool doesn't have full redundancy for some data, and you can't tell if a pool has DTL entries, are you saying there's no way to tell if the current state of your pool could survive a device failure? If a resilver successfully completes, barring another device failure, doesn't that mean the pool is restored to full redundancy? I feel like I must be misunderstanding something :(. Thanks... -- Paul B. Henson | (909) 979-6361 | http://www.csupomona.edu/~henson/ Operating Systems and Network Analyst | hen...@csupomona.edu California State Polytechnic University | Pomona CA 91768 _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
