Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi Bret, > Intel(R) Xeon(R) CPU E3-1230 V2 @ 3.30GH > CentoS 6.5 - 2.6.32-431.17.1.el6.x86_64 > drbd version: 8.3.16 (api:88/proto:86-97) please use 8.4.4 (or .5). Eg because of http://blogs.linbit.com/p/469/843-random-writes-faster/ > dd if=/dev/zero of=./testbin bs=512 count=1000 oflag=direct > 512000 bytes (512 kB) copied, 32.3254 s, 15.8 kB/s This means ~32msec per write. But: you're writing into a _filesystem_, not directly onto the DRBD resource. And that means quite some write amplification - each 512 byte write _might_ result (depending on the filesystem) in _multiple_ write- requests, each with a separate barrier ... Please try writing into a DRBD device, without any filesystem inbetween; and using 4kB blocks might help to avoid read/modify/write cycles, too.