Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hello, I have (almost) exactly the same problem as http://lists.linbit.com/pipermail/drbd-user/2011-December/017405.html Debian 6.0.2 DRBD 8.3.7, dual primary, protocol C LVM DRBD allows to write at high speeds (20MB/s first seconds), then the speed falls and drbd blocks even after I kill dd. However when i run dd with oflag=direct, write speed is about 10kb/s! The network latency is quite high (0.200ms) and the systems are virtualized, so I haven't enabled disk/md barriers/flushes, because I don't trust all the IO layers under the DRBD. Is there any way to shrink/disable that caching? How should I tune the drbd network settings for better performance in such a high-latency environment? (I mean especially those buf sizes.) As you can see from the pastebin entries (below), load is quite high even when idle. How does file access with DRBD & OCFS2 work? I suppose that a node can read a file without having to interact with the second one (without locking). Example of idle behavior: http://pastebin.com/raw.php?i=YjQW05Us During dd writing with oflag=direct on another node: http://pastebin.com/raw.php?i=gvCQkBQ7 You can get the dstat plugin on my web: http://lefty.ofight.org/howto/drbd-dstat-plugin