Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi Lars, Am Donnerstag 25 Oktober 2012 11:24:05 schrieb Lars Ellenberg: > On Tue, Oct 23, 2012 at 11:03:14AM +0200, Thilo Uttendorfer wrote: > > Hi, > > > > the man-page of drbd.conf says about protocol B "...completed, if it has > > reached local disk and remote buffer cache". > > > > How can I determine the size of the remote buffer cache? Is this cache > > also limited by the "max-buffers" option? > > DRBDs max-buffers settings has something to do with it, > but that does not change between DRBD protocols. > > There are pictures somewhere in those "papers" linked from the > documentation page. iirc. thanks for the explanation! What I'm interested in is a setup with 2 different systems: One with a very fast SSD and one with a much slower regular disk. I understand protcol "B" like that: If you write lots of data on the fast (drbd primary) system the "remote buffer cache" on the slow (drbd secondary) system will be filled because writing to the local disk will take longer. If this cache is full, the write performace will decrease on the primary. Reading from disk will always be fast because the slow system is not involved. Is my understanding of protocol "B" correct? Now, to decide if this setup makes sense, it is important to know how big the "remote buffer cache" is or how I can increase it. Can you give me a hint how to determine and/or change the size of the remote buffer cache? Thank you very much, Thilo -- Thilo Uttendorfer Linux Information Systems AG Putzbrunner Str. 71, 81739 München Fon: +49 89 993412-11, Fax: +49 89 993412-99 tuttendorfer at linux-ag.com, http://www.linux-ag.com