From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Robinson <john.robinson@anonymous.org.uk>
Subject: Re: RAID5 created by 8 disks works with xfs
Date: Sun, 01 Apr 2012 13:28:54 +0100
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On 01/04/2012 11:33, David Brown wrote:
[...]
> For an application like this, it would probably make sense to put the
> xfs log (and the mdraid bitmap file, if you are using one) on a separate
> disk - perhaps a small SSD.

Now that you've suggested that, it occurs to me that for an application 
like this, the OP might be better doing his multiple slow streams to a 
spool folder on SSD, and copying over to the big array of spinning rust 
when each stream completes. 200 streams of 500MB is 100GB of data, so a 
pair of slightly larger SSDs in RAID1 (or RAID10, to balance the reads 
coming off) would do nicely as a spool area.

This might also be a good application for bcache, FlashCache or whatever.

Cheers,

John.