On 12/12/2010 00:49, Stan Hoeppner wrote:
Since Javier is looking for ways to decrease I/O load on the SAN, not necessarily increase Dovecot performance, I think putting the index files on a ramdisk is best thing to try first. It may not be a silver bullet. If he's still got spare memory to add to this guest, doing both would be better. Using a ramdisk for the index files will instantly remove all index I/O from the SAN. More of Dovecot's IMAP I/O is to the index files than mail files isn't it? So by moving the index files to ramdisk you should pretty much instantly remove half your SAN I/O load. This is assuming that Javier currently stores his index files on a SAN LUN.
Speaking of ramdisk/SSD, has anyone tried a PCIe SSD for indexes?
~Seth