On 20/12/15 07:36, Phil Turmel wrote: > Hi Steven, > > On 12/19/2015 09:34 AM, Steven Haigh wrote: > >> I've always used the whole disk for the RAID6 - as from what I >> understand, this gives the best layout for various drives - no matter if >> they're 512 or 4096 byte sectors. >> >> Is this still the case? > > There's no real advantage other than an itty bit of space. If my case > was too small to have a separate mirror for my OS, I'd make three > partitions on everything for boot, LVM root & etc (raid10), and bulk > storage (raid6). When I have room for the mirrored OS (boot & LVM), I > use whole disks for the bulk storage. Yes, I have two separate disks in RAID1 as the boot / VM guests - the RAID6 is used for bulk storage. The chassis has a total of 10 hot swap bays, with 5 used by the RAID6, 2 by the RAID1 and 3 spare. I get resync speeds of around 170Mb/sec on the RAID1. >> I've noticed that my resync speeds on this RAID6 hover around 60Mb/sec - >> which I was expecting to be a bit quicker (although I haven't tested >> speeds on this array for years). > > Consider using small chunk sizes for parity raid if there's even the > slightest random access usage. See the list archives for the past > couple weeks for a long thread on performance. There's many > optimization possibilities. I have tried to keep up with those couple of threads - but I've found it hard to follow across the length of time they've been going. A summary of the findings in those threads with experimentation would be fantastic! It seems that actual data beyond "increase --setra on /dev/sd[.] and increase the stripe_cache_size is about all I find via Google - and that data is years old... -- Steven Haigh Email: netwiz@xxxxxxxxx Web: https://www.crc.id.au Phone: (03) 9001 6090 - 0412 935 897
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