[DRBD-user] Storage on Rum & Kugel ?

Werner Fischer werner.fischer at fh-hagenberg.at
Thu Sep 4 11:11:24 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 Wed, 2008-09-03 at 09:45 +0200, Lars Ellenberg wrote:
> 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.
I have done some tests with a very nice perl script from
http://brad.livejournal.com/2116715.html with different RAID controllers
(Adpatec, Areca, 3ware, and SATA-onboard) and documented the results (in
German) here:

One of the controllers I've tested was an Adaptec 5405 - with this
controller you can use the arcconf CLI tool from Adaptec to disable the
cache of a disk, e.g. for the first disk:
arcconf SETCACHE 1 DEVICE 0 0 wt

PS: I've also done some consistency tests and provided some infos on
that, too:

best regards,

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