On Wed, Mar 5, 2014, at 8:08, Karl Pielorz wrote: > > Hi, > > I have a couple of FreeBSD 10 systems I've setup HAST on - this seems to > work well, but I've noticed the read performance of local /dev/hast/* > devices is around half of the normal raw device? > > e.g. a dd from an SSD as /dev/da0 nets around 220Mbyte/sec - the same dd > run against the same device when setup with hast (i.e. /dev/hast/disk1) > only nets around 110Mbyte/sec. > > I realise another layer is going to affect performance (and this may just > be the price you have to pay) but is there anything likely tunable for > this? > > If I fail the other node (so I'm running the test against a 'degraded > primary') it's still as slow [as you'd kind of expect, as reads were/are > only local] > > I've setup ZFS on top of the hast devices - again this seems to work OK, > but you can really see the performance difference when doing a pool scrub > on hast backed devices vs. the raw ones... >
Which HAST replication mode are you using? Fullsync? Do you have atime enabled on that filesystem? I'd expect it to act like a local disk without any significant penalties unless you're doing writes and they're waiting to be synced before the next read. _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-geom To unsubscribe, send any mail to "[email protected]"
