[DRBD-user] 0.6 vs. 0.7 3ware performance? [Was: Expected syncspeed for a 425gb volume?]

Jeff Buck jeffb at umci.com
Wed Apr 13 02:36:00 CEST 2005

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


On Tue, 2005-04-12 at 13:03 -0500, Nate Carlson wrote:
> > back, write, and seek random again. The problem being that the 3ware
> > raid card is splitting the writes into 64k chunks on the different
> > disks, causing them all to do a little dance after every 64k write. We
> > have a bunch of the "JD" drives.. I guess the ones that don't have this
> > behavior are the "SD" drives (unavailable when we started this project).
> 
> Makes a lot of sense - we've actually got two seagate and two WD (JD)
> drives on each controller.

I still suspect that there's a bit more going on with the 3wares though.
I've yet to see anyone report any decent performance with them. Surely
someone's got a setup without the peculiar WD drives. I'm thinking that
there's still something about the 3wares or their drivers that doesn't
get along with drbd at all. Maybe drbd 7 is more touchy about latency in
the hardware?

We've had problems with our WD "JD" drives dropping out of our array
spontaneously also. One of the WD techs said that if we RA them, and
tell them we're using them in a raid array they'll send us the "SD"
version of the drive back. So far we've only got one of the drives back,
but it's a nice shiny new "SD" drive this time, so it looks like he was
correct. It might be an option for anyone that thinks this might be
their problem.

We've got 46 more drives to RA still, and they only let you do 5/day,
one at a time, so beware.... It could take a while if you've got a lot
of drives.





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