> Jef Pearlman wrote: > > Absent that, I was considering using zfs and just > > having a single pool. My main question is this: what > > is the failure mode of zfs if one of those drives > > either fails completely or has errors? Do I > > permanently lose access to the entire pool? Can I > > attempt to read other data? Can I "zfs replace" the > > bad drive and get some level of data recovery? > > Otherwise, by pooling drives am I simply increasing > > the probability of a catastrophic data loss? I > > apologize if this is addressed elsewhere -- I've read > > a bunch about zfs, but not come across this > > particular answer. > > We generally recommend a single pool, as long as the > use case permits. > But I think you are confused about what a zpool is. > I suggest you look > t the examples or docs. A good overview is the slide > show > http://www.opensolaris.org/os/community/zfs/docs/zfs_ > last.pdf
Perhaps I'm not asking my question clearly. I've already experimented a fair amount with zfs, including creating and destroying a number of pools with and without redundancy, replacing vdevs, etc. Maybe asking by example will clarify what I'm looking for or where I've missed the boat. The key is that I want a grow-as-you-go heterogenous set of disks in my pool: Let's say I start with a 40g drive and a 60g drive. I create a non-redundant pool (which will be 100g). At some later point, I run across an unused 30g drive, which I add to the pool. Now my pool is 130g. At some point after that, the 40g drive fails, either by producing read errors or my failing to spin up at all. What happens to my pool? Can I mount and access it at all (for the data not on or striped across the 40g drive)? Can I "zfs replace" the 40g drive with another drive and have it attempt to copy as much data over as it can? Or am I just out of luck? zfs seems like a great way to use old/unutilized drives to expand capacity, but sooner or later one of those drives will fail, and if it takes out the whole pool (which it might reasonably do), then it doesn't work out in the end. > > As a side-question, does anyone have a suggestion > > for an intelligent way to approach this goal? This is > > not mission-critical data, but I'd prefer not to make > > data loss _more_ probable. Perhaps some volume > > manager (like LVM on linux) has appropriate features? > > ZFS, mirrored pool will be the most performant and > easiest to manage > with better RAS than a raidz pool. The problem I've come across with using mirror or raidz for this setup is that (as far as I know) you can't add disks to mirror/raidz groups, and if you just add the disk to the pool, you end up in the same situation as above (with more space but no redundancy). Thanks for your help. -Jef This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
