JP Howard wrote: > > On Thu, 31 Oct 2002 23:29:57 -0700, "Andreas Dilger" > <[EMAIL PROTECTED]> said: > > When people were testing this with ext3 external journals, they just > > used a RAMDISK for getting the performance measurements. Obviously, > > (I hope ;-) this is not something you can do in real life, but for > > performance measurement it is OK. > > > > Most people found that the ramdisk (and presumably the NVRAM device too) > > didn't perform much, if any, better than having a separate fast disk for > > the journal, because you are doing sequential I/O to the journal anyways. > <...> > > Yes, I'd heard something like this. Our servers aren't going to have a > spare drive bay, I think, so a PCI NVRAM card may turn out to be a more > economical solution (although I haven't received quotes back from the > vendors yet...). > > If I do find a spare drive bay, how unsafe would it be to use a single > drive, rather than RAID 1 mirroring? What does ReiserFS do if it gets an > IO error on the journal device?
Reiserfs will want you to do following: #reiserfsck --no-journal-available main_device or #reiserfsck --no-journal-available --rebuild-tree main_device then specify new journal device by reiserfstune. >Could that bring down our whole system? I > assume that it would--in which case using NVRAM would actually save two > drive bays, since it should be reliable enough to not need redundency. > > So, how big is a ReiserFS journal when using data=journal anyways?... 8192 blocks for reiserfs with standard journal. The size of external journal device for non-standard. Edward.
