Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi Roland, I've analysed the DRBD 8.4.1 kernel code some time ago. DRBD has a dynamic IO request size detection which always starts at 4 KiB. If you've got a connection to the other system, then it negotiates a higher IO request size (128 KiB because of hashing functions). If you loose the connection, it's 4 KiB again. You can use the tool "blktrace" to trace how big the IO requests are. Or you can look at /sys/block/drbd0/queue/max_sectors_kb. IMHO this must become settable to the limits from the devices below if you already know that "max_sectors_kb" is completely equal on both sides. See: http://www.gossamer-threads.com/lists/drbd/users/24104 Cheers, Sebastian On 26.09.2012 14:50, Roland Kaeser wrote: > Only the drbd is very slow. (Single node, just to test write > perfomance on local block device.