----- Original Message ----- From: "Aaron Paetznick" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, March 16, 2004 4:28 PM Subject: Re: [Mimedefang] ramdisks on Linux
> Yeah I was just shooting from the hip trying to find some other way to > remove as much I/O from my physical disks as possible. I'm building a > pool of more-or-less "disposable" front-end filter servers. If I could > move EVERYTHING of any significant I/O onto a ramdisk, I might be able > to get by with cheap/slow SATA drives, even for a machine with very high > load. Also look at hardware ATA RAID controllers such as the 3ware Escalade. You can mirror/stripe disks to gain performance. Put enough disks in the array and you can beat a smaller number of SCSI disks handily. The Escalade uses hardware for RAID5 checksum calculation if you go that way, which is a significant performance boost over doing it in software. You can get an older-model Escalade 7000 or 7500 PATA controller for a couple hundred $$$. Mount your disks with the "noatime" option to cut down on largely useless disk writes. Put a LOT (2GB or more) of RAM into your system and let the O/S use the extra for filesystem caching. > Are there any other directories I could consider running on a ramdisk? > Are there any "write-through" ramdisk options that might be sendmail > mqueue safe? /etc/mail/spamassassin/bayes ... Putting the Bayesian database on a RAMdisk is a great performance boost, but you need to remember to back it up every day or week (it doesn't hurt to lose a few days of data), and restore the backup whenever the system boots. This is a big win. /var/spool/MIMEDefang ... Putting the MIMEDefang spool files (but not the quarantine) on a RAMdisk is safe and helps performance. This is a big win. /var/spool/mqueue/xf if you split your spool files across several directories. NEVER mount the /df or /qf directories on a RAMdisk, since you can lose mail when your system crashes or is rebooted. This should be a moderate win. /etc/mail ... This is a "read-only" directory for normal mail operation (all changes are manual, and infrequent), just restore it's contents whenever the system boots. Sendmail reads these files each time a new sendmail process is created, and some of the files for each mail message. Don't forget that you'll have to update the on-disk copy of the configuration files on those rare occasions when you actually have to. This is likely a small win since the most commonly used files will be in the filesystem cache anyway... Chris Myers Networks By Design _______________________________________________ Visit http://www.mimedefang.org and http://www.canit.ca MIMEDefang mailing list [EMAIL PROTECTED] http://lists.roaringpenguin.com/mailman/listinfo/mimedefang
