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Bug#598633: linux-image-2.6.32-5-amd64: /proc/sys/dev/raid/speed_limit_max defaults to 200000 without apparent reason

On 30/09/10 18:43, Bastian Blank wrote:
On Thu, Sep 30, 2010 at 05:14:44PM +0100, Tim Small wrote:
/proc/sys/dev/raid/speed_limit_max defaults to 200000 - unnecessarily
limiting software RAID performance, I can't see a reason for this limit
which seems a bit arbitrary....
Please explain. This limits the bandwidth allocated for for rebuild and

Sorry for the terse report. On machines which are readily purchasable, this default will unnecessarily cap the rebuild and check speeds for md RAID arrays. e.g. a 4 drive RAID10 made with 7200rpm SATA drives is likely to exceed this cap with an unlimited rebuild/check speed of 240000 or so, as would a RAID1 with two ~100 usd SSDs.

During the lifetime of squeeze, this limit is likely to be hit more and more frequently... AFAIK it has defaulted to "200000" for ages, it's only now that commonly available hardware is starting to hit this limit.


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