Have you thought about a 3-way mirror instead of RAID-Z? I started with RAID-Z2 and went to a 3-disk mirror. Reads are faster, and I haven’t noticed any degradation at all when writing vs the RAID-Z2 configuration I used to have. Plus CPU time isn’t an issue for mirrors.
There are several articles talking about the different strategies, and they’re easy to find. Here are a few: http://constantin.glez.de/blog/2010/01/home-server-raid-greed-and-why-mirroring-still-best https://blogs.oracle.com/roch/entry/when_to_and_not_to http://blog.richardelling.com/2010/02/zfs-data-protection-comparison.html http://blog.delphix.com/matt/2014/06/06/zfs-stripe-width/ http://queue.acm.org/detail.cfm?id=1670144 Hope this helps. Regards, John On Jul 7, 2014, at 11:08 AM, Ibrahim Tachijian via smartos-discuss <[email protected]> wrote: > Hey Joyent and every other smartos user. > > We are trying to narrow down a few of our hardware choices to meet our > requirement. > > Our requirements is well defined and we know exactly what we expect from the > proposed array. > We have barely any CPU power necessary so a single quad core is enough for us. > > Requirements: > > Write operations: (24/7) > Approx 200 consecutive writes each write at 5mbit/s > [Total: 125MB/s writes] > Read operations (150 consecutive reads is the UPPER limit, might be less). > Approx 150 consecutive reads each read at 5mbit/s > [Total: 93MB/s reads]. > Storage capacity 15TB of actual space (Not counting space lost to RAIDZ > levels or mirrored vdevs) > Our proposal is: > > E5-1620v2 (Quad 3.7ghz Xeon) > 128gb of DDR3 ECC REG RAM > SAS Disks from HGST (Count and Size of each drive to be determined) > Proposed drive HGST SAS HUS724040ALS640 > > > ZFS "sync" setting set to disabled. Data loss is not an issue for us, we only > care about performance. > Dedupe off, compression off (We're saving video) > ZIL is unnecessary because of "sync" disabled. > RAIDZ level? We are unsure. > Given these parameters, and the experience joyent has had with HGST 4TB SAS > drives. How large of an array, and what RAIDZ or mirrored vdev (raid10-like) > would I require to be able to meet my above mentioned requirements? > > Regards, > > -- > Ibrahim Tachijian > smartos-discuss | Archives | Modify Your Subscription ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
