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