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, Jun 07, 2007 at 10:46:31AM -0700, Ben wrote: > Does anybody have any advice for tuning DRBD 0.7? I'm not seeing much > out there except for some un-explained bullet points for a hacked > version for use with OpenSSI, and I don't know how much of that > advice is due to assumptions that are only true for OpenSSI. Some > specific questions I have are: > > 1. What are the tradeoffs with changing al-extents? smaller al-extents * more frequent meta data updates (synchonous sector writes), introducing more frequent maximum latency writes. * smaller area to resync after primary crash, less mimimal resync time. > 2. Can I eck out more throughput by increasing sndbuf-size? Does that > increase my write latency when using Protocol C? most likely not. > 3. What's a reasonable formula for determining max-buffers? Does > increasing them imply I should increase something else too? if you go too high, you should increase your physical RAM :) but don't tune that up too high. that number is basically in "pages", iirc, so if you compare (max-buffers * 4k * number of drbd's in use) to your physical RAM, it should be some not too impressive number. or you might say hello to the oom killer :) > 4. Does anybody know if the Areca raid cards like high or low unplug- > watermark settings? sorry. you have to try... > 5. Does decreasing max-epoch-size reduce my write latency? most likely not. > Does anybody have any experience playing with the schedulers in the > 2.6 kernel? yes of course. but the answers here depend very much on what you specifically ask for. -- : Lars Ellenberg Tel +43-1-8178292-0 : : LINBIT Information Technologies GmbH Fax +43-1-8178292-82 : : Vivenotgasse 48, A-1120 Vienna/Europe http://www.linbit.com : __ please use the "List-Reply" function of your email client.