Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
External metadata brings some advantages over internal metadata, especialy when it comes to resizing as well as recovery. If you want to maximize speed for metadata you could use a ssd connected to a dedicated controller. Given the small diskspace needed for metadata and the rather low price of such ssd nowadays this is probably the best solution. if you want to migrate existing partitions to DRBD external metadata AFAIK is the only way to do it Mit freundlichen Grüßen / Best Regards Robert Köppl Systemadministration KNAPP Systemintegration GmbH Waltenbachstraße 9 8700 Leoben, Austria Phone: +43 3842 805-910 Fax: +43 3842 82930-500 robert.koeppl at knapp.com www.KNAPP.com Commercial register number: FN 138870x Commercial register court: Leoben The information in this e-mail (including any attachment) is confidential and intended to be for the use of the addressee(s) only. If you have received the e-mail by mistake, any disclosure, copy, distribution or use of the contents of the e-mail is prohibited, and you must delete the e-mail from your system. As e-mail can be changed electronically KNAPP assumes no responsibility for any alteration to this e-mail or its attachments. KNAPP has taken every reasonable precaution to ensure that any attachment to this e-mail has been swept for virus. However, KNAPP does not accept any liability for damage sustained as a result of such attachment being virus infected and strongly recommend that you carry out your own virus check before opening any attachment. Mark Morlino <mrmorlino at alaska.edu> Gesendet von: drbd-user-bounces at lists.linbit.com 14.01.2011 08:40 An drbd-user at lists.linbit.com Kopie Thema Re: [DRBD-user] difference in speed when using external metadata On Mon, Jan 10, 2011 at 10:31 AM, Bart Coninckx <bart.coninckx at telenet.be> wrote: > On Monday 10 January 2011 19:40:17 J. Ryan Earl wrote: >> On Sun, Jan 9, 2011 at 10:03 AM, Bart Coninckx > <bart.coninckx at telenet.be>wrote: >> > Hi all, >> > >> > am reading the Novell docs on DRBD and one of the ways they mention to >> > speed >> > up DRBD is using external metadata. Possibly a hard question to answer >> > but could someone indicate by what degree this would enhance speed >> > (provided using >> > a sufficient fast disk for the metadata, like a SSD)? >> > >> > thx! >> > >> > Bart >> >> A RAID controller with a backed-write cache essentially nullifies >> any advantage there. A RAID controller that can instantly return on >> FUA-writes is what you want. >> -JR > > Hi, > > so the essence of your answer is that this is not a matter of having metadata > internal or external, but rather of having the right RAID controller? > Do you have examples of these in the major brands (HP, Dell, ...) ? > > thx! > > > > B. > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > I would be interested in this information too (in my case I'd be interested in any supermicro controllers that meet this requirement). If I understand correctly, an FUA-write is a write-through request. Doesn't that mean that the controller should not return until everything has been physically written to the disk? It seems to me that in order to return instantly on an FUA-write, the controller would have to ignore the FUA request and return once the data has been written to the cache. I don't see how it can both force physical disk access and return instantly. Perhaps I'm missing something, it certainly wouldn't be the first time. -Mark _______________________________________________ drbd-user mailing list drbd-user at lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20110114/72613c6c/attachment.htm>