Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Andreas Huck wrote: > Hi, > > On Monday 26 April 2004 22:10, Andreas Semt wrote: > [...] > >>Right now i had the same phenomenon: A load average of 16 (!) and cpu >>almost idle. No (read/write) access to the partition on the drbd device >>possible! >>Can i see what causes that "hang" i.e. the processes who read/write do >>that partition/drbd device? >>Can i enable a debug mode of drbd to see if drbd has something to do >>with that? >>Can I see some kernel messages regarding disc access? >> >>THANKS for help! That problem is REALLY annoying! > > > have you monitored the disk IO load (e.g. vmstat 1)? If it stays high > than maybe your RAID is trying to catch up - and your system waits > for it patiently. > Does disabling the hardware RAID cache change the behavior? > No, at this moment I did not monitored with vmstat. The problem is, that the "hang" occurs at random, so i have to wait or simulate it to monitor. Also I don't believe it's the RAID write cache, because the system and the drbd devices are located on the same RAID 5 array and i had no problems to access the system partition during the "hang". Are there any tools to generate disk load on a particular block device and to monitor read/write precesses on that device (like an "i/o test suite")? Other hints (perhaps how to make drbd more communicative)? -- Best regards, Andreas Semt