[DRBD-user] Hardware-recomendation needed

Digimer lists at alteeve.ca
Tue Apr 3 19:07:49 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 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.

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



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