Date: Wed, 05 Mar 2014 14:08:09 +0000 From: Karl Pielorz <kpielorz_lst@tdx.co.uk> To: freebsd-geom@freebsd.org Subject: HAST local read performance? Message-ID: <B62B94E66C2B63D3894AB7DF@Mail-PC.tdx.co.uk>
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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... -Karl
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