[Varnish] #751: Varnish on SSD

[Varnish]

#751: Varnish on SSD
-------------------------------+--------------------------------------------
 Reporter:  anand_happs        |        Type:  enhancement
   Status:  new                |    Priority:  normal     
Milestone:  After Varnish 2.1  |   Component:  build      
  Version:  trunk              |    Severity:  normal     
 Keywords:                     |  
-------------------------------+--------------------------------------------
 I'm contemplating setting up a varnish cache on a system with SSD drives.

 The obvious benefit is that these systems have great READ speeds and I
 expect my hit ratios to be fairly high.

 Let's assume I can put 7 SSDs in to a RAID configuration. (there are some
 cases that will let me pack in much much more)

 Implementation questions:

 Should I use RAID0? (I expect a drive to fail eventually, so this seems
 dangerous.)

 Should I use RAID10? (This halves my disk footprint, which is costly.)

 Should I use RAID5? (SSDs are known to have "bad" write performance and
 write limits, and all the extra parity writes may slow this down
 considerably.)

 Should I just treat each disk as it's own squid datastore? (how well does
 squid handle multiple data stores? and what happens if/when one fails?)

 Should I ignore datastores and just make the SSDs in to large SWAP
 partitions and let the linux VM do it's thing? (seems sloppy)

 Any advice from you using SSDs in production environments would be greatly
 appreciated. (esp if you're using them for HTTP caches)

 Also how difficult it is for a varnish cache to allow users manage data
 life cycle policy from SSD/NAND flash drives (fusion IO's) to disk. Meta
 data controlled by a policy which can be modified by users.

-- 
Ticket URL: <http://varnish-cache.org/ticket/751>
Varnish <http://varnish-cache.org/>
The Varnish HTTP Accelerator