On 25.10.2013 00:12, Lists wrote:
On 10/24/2013 03:48 PM, Karanbir Singh wrote:
On 10/23/2013 10:30 AM, Morgan Cox wrote:
If you want SSD + MDRAID you need to use a 3.8+ kernel to have TRIM.
The speed difference between the stock 2.6.32 -> 3.10 kernel with SSD + MDRAID is insane.
has someone quantified what this 'insane' amounts to ?
Going from HDD to SSD's gave us better than a 95% reduction in query times for complex queries using PostgreSQL on otherwise identical hardware. I wouldn't have believed it had I not seen it directly, for myself.
That's great, but it's not an answer to what has been asked. Have you tried SSD based software raid on stock kernel and on kernel-ml, have you noticed any big difference?
I guess there should be some difference, software raid is not capable of TRIM in stock kernel, but I'm also not sure if a newer kernel is all that's required, perhaps modifications to mdadm tool are also necessary.
Lucian