[DRBD-user] Storage on Rum & Kugel ?

Lars Ellenberg lars.ellenberg at linbit.com
Wed Sep 3 09:45:14 CEST 2008

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

On Thu, Aug 28, 2008 at 10:39:30PM +0200, Robert Heinzmann (ml) wrote:
> Hello,
> I just watched the recording of the performance tuning webinar. The Q&A  
> points to  
> http://www.drbd.org/community/wiki/?tx_drwiki_pi1%5Bkeyword%5D=performance 
> for the specs of rum & kugel.
> I wonder what storage subsystem on rum & kugel looks like ? (Controler +  
> HDD) ?

ah, right.
that is an Adaptec 3405 RAID5 V1.0
with battery backup unit for the cache
with 4x FUJITSU MAX3073RC in RAID5
as PV of LVM2.
drbd and everything else is sitting in LVs on that.

btw, when you have a non-volatily,
battery backed up write cache in the controller,
don't forget to disable the (typically volatile!) on-disk cache.
or you may face data loss on power outage anyways.
you may enable the read cache on disk, if you think it is worth it.

in this setup, that was done by
modprobe sg
for i in `seq 4`; do sdparm -s WCE=0,RCD=0 -S /dev/sg$i ; done

see man sdparm for details,
and your controller manual for other ways to achieve the same
if the single disks are not visible as sg devices to the OS.


: Lars Ellenberg                
: LINBIT HA-Solutions GmbH
: DRBD®/HA support and consulting    http://www.linbit.com

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