Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
>On Sat, Feb 11, 2012 at 7:30 PM, Pascal BERTON <pascal.berton3 at free.fr> wrote: >> Florian, >> >> I've watched your video, very interesting indeed... Unfortunately for you it >> raised some more questions to me :-) >> First, just to be sure I correctly understood : flashcache will only (But >> significantly) improve read operations, no impact or so on writes right ? >It's a write-back capable device, so if you configure it in that mode, >of course it will have an impact on writes. Ah right, I remember you mentioned it in the video now... >> Then, a year or 2 ago I had the opportunity to play around with Ming Zhao's >> dm-cache (completely apart from DRBD by the way, it was a standalone >> system), and to what I remember it roughly looked like this flashcache thing >> I didn't know of, except it makes use of a ramdisk instead of an SSD drive >> (And it has an impact on write operations, as far as I remember). I >> immediately see one advantage compared to flash-cache : it would (should?) >> be more performant, being memory-based instead of IO-based. However, >> inconvenient, it would be certainly smaller. >> Have you ever had the chance to add that dm-cache feature to DRBD the way >> you did it with flashcache ? Do you know/think it would work efficiently >> with DRBD ? And, lastly, do you think it would make sense to think of >> combining dm-cache and flashcache together to get kind of an L1+L2 storage >> cache level pair ? >As far as I'm informed there are currently three generic block-layer >caching devices available on Linux: flashcache, dm-cache and bcache. >Of those, only bcache seemed to be seriously interested in a push >towards mainline until recently (though that may be changing). As for >myself I have zero experience with bcache and dm-cache, so flashcache >is the only one I can comment on. >Hope this helps. What's your intended use case? Oh, simply get faster and faster... :) Any brick that allows me to improve perfs is of potential interest to me. Especially in virtualization where storage perf is key. BTW, I didn't know of bcache either, so that's another one I have to dig into. Thanks for your answers! Best regards, Pascal. >Cheers, >Florian -- Need help with High Availability? http://www.hastexo.com/now _______________________________________________ drbd-user mailing list drbd-user at lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user