We've been noticing some problems with ext3 and, in our case, postfix, that appear to come to light under heavy disk i/o loading. A previous thread found here (http://www.redhat.com/mailing-lists/ext3-users/msg04189.html) documents an identical set of symptons (and similar setup), but with RH 7.2 The specifics are this: 1. Stock install of RH8.0 with postfix. 2. Linux mx 2.4.18-14 #1 date i686 i686 i386 GNU/Linux 3. Email list delivery to ~40,000 recipients, each with their own customized msg. (In other words, these are 40K unique messages going out, not one msg to 40K unique recipients). 4. Postfix parameters (processes) and system resources such that no file swapping occurs. (1 Gig processor, 80 Gig 7200 RPM drives, 1 Gig RAM) 7 distinct processes on another system start firing off as fast as they can email to this system which then deilivers it as necessary to other mx servers. The results are interesting: 1. Very quickly while running "vmstat", one will see decent "bo" activity corresponding to the acceptance of the various messages, and context switches in the neighbourhood of 30-40,000 per second. 2. After about 10-15 seconds, "bo" activity drops to ZERO, and context switching ramps up to about 1,000,000 per second. After a while, the context switches drop back down, and we're back to seeing heavy "bo" activity. 3. After cycling through the behaviour in step 2 several times, (after 3-4K msgs are delivered), the context switching remains high, and "bo" activity remains at zero. 4. Examining the system with "top" shows a huge run queue - all smtp processes are running full tilt. This above set of conditions were repeated numerous times after reboots. Finally, taking the heavily used disk partition (/var) and setting it to ext2 and rebooting and resuming mail delivery, absolutely NO problems occur. To summarize: the mail configuration works in an old RH6.2 setup, in RH8.0 with ext2, but makes the system unusable with RH8.0 with ext3. On numerous other non-heavily loaded systems, we've never had problems with ext3 (all RH8.0 base). Cheers, Thomas _______________________________________________ Ext3-users@redhat.com https://listman.redhat.com/mailman/listinfo/ext3-users
