[DRBD-user] Hardware-recomendation needed

Digimer lists at alteeve.ca
Tue Apr 3 19:11:50 CEST 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


On 04/03/2012 10:07 AM, Digimer wrote:
> On 04/03/2012 02:53 AM, Lukas Gradl wrote:
>> As we've just space for one 3.5" HDD (the other bay is used by the
>> Boot-SSD) I'm unable to install a raid5-setup.
> 
> Three things;
> 
> 1. RAID 5 will shorted the life of SSDs.
> 2. RAID 1+0 is faster than RAID 5, if you can afford the reduced capacity.
> 
> 2. cat /sys/block/sdb/queue/rotational
> 
> If set to '1';
> 
> echo 0 > /sys/block/sdb/queue/rotational
> 
> That made a significant improvement on my test bed (albeit with hardware
> RAID 5 [LSI-9265 w/ SSDs and HP P410i w/ 10krpm SAS HDDs).
> 
> As for dual-primary/Protocol C; I've got nine clusters in production,
> some under heavy load, hosting both Linux and Windows VMs. These operate
> just fine, with proper config of the storage. For example; in some
> cases, I use a couple separate RAID 1 arrays, in others I used RAID 5.
> All use traditional platter drives (some SATA, most SAS). None of these
> clusters are over the top, performance wise.

Oh, you might want to try testing with different schedulers;

cat /sys/block/sdb/queue/scheduler  (try 'echo deadline|cfq|noop > /...').

cat /sys/block/sdb/device/queue_depth   (try 64, 128, ... 975, 128 was
my best).

There are other tweaks, but that should get you going.


-- 
Digimer
Papers and Projects: https://alteeve.com



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