On Fri, 2 Nov 2012, Peter Ross wrote:
Just for ZFS (under FreeBSD): I have throttle inbetween (15 Megabit/second) because it was "hammering" the disks to a stand still for the rest of the system.
Yep, this, the 20% free space and the generous use of RAM are my main issues with ZFS but they are not big enough to outweight the advantages I see in everyday administration.
"Generous memory usage" indeed. My zfs server with 4GB of ram crashes once a week on average with zfs arc backtraces or just livelocks with txg_sync taking 100% CPU usage (with no zfs access, which is bad for a machine with zfs mounted /var by necessity of /boot being a 128MB flash IDE card and / being a 8GB USB nanostick). Each -rc release says "we finally fixed that txg_sync and arc_reclaim issue", but alas it never comes good. My favourite is where sometimes mysteriously arc usage increases tens of times beyond arc_max before the machine grinds to a halt. Someone ballsed up the memory accounting! (Just saying this just in case anyone thought zfs was preduction ready yet. Apparently the same issues sometimes affects bsd and indiana).
The snapshots (and zfs send/receive - I mirror every mission-critical filesystem to a "partner" machine) are part of the advantages, it is all very easy.
I am surprised people find zfs send so useful though. My only use for it would be if I could get data of it onto another filesystem at close to wire speed :) I mean, I thought it was pretty routine back in days of yore to do an: lvm snapshot dd if=/dev/base/home-snap | ssh blah dd of=/dev/base/home Ok, a couple more commands, but infinitely flexible. -- Tim Connors