On 10/04/12 12:20, Trent W. Buck wrote:
Toby Corkindale wrote:
It sounds like a good idea at first, but every time you need to reboot one or other of the iscsi targets (eg. for kernel updates or suchlike) you'll need to rebuild the RAID array, and the performance of that over ethernet blows.
Didja have write-intent bitmaps on? Not sure[0] if they help in that case...
No, pretty sure they didn't. I didn't build the systems in question, so not sure why not -- maybe it just wasn't considered stable back when Debian Etch was the stable platform? *shrug* The rebuild performance (while there was also active i/o going on) was still cripplingly slow though. Also worth noting that the md layer and the iscsi layer didn't interact all that well -- if the iscsi target dropped out, I seem to remember that the md layer didn't respond quickly. It wasn't like with disks, where it'd kick out a non-responding disk soon and keep going -- instead it'd hang for aeons. This might have improved in more recent kernels.. Toby