Or how we got distracted while installing the new mail server...
July, 11 2002
Part one of a five page article
page 1 page 2 page 3 page 4 page 5
Our existing mail server, a Cobalt Raq3 running Red Hat Linux 7.1 started having hardware problems and needed to be replaced. This prompted discussion on if we should continue to use qmail, or migrate to Postfix (now included with Red Hat Linux 7.3, our Linux distro of choice (and yes, we've used them all, including Gentoo). Another decision to make was what filesystem to use. We decided to stick with filesystems included with the stable kernel, so that meant either ext3 or reiserfs. This required some benchmarking to settle the question.
It is a little know fact that Red Hat Linux 7.2 and above can be installed using reiserfs by passing the reiserfs option at the initial installation prompt. In Disk Druid, reiserfs becomes a selectable filesystem type. This makes installing with reiserfs an easy task.
Hardware Specs:
- Dell PowerEdge 1650
- Intel Pentium III 1133MHz 512 KB L2 cache
- 768MB 133MHz ECC SDRAM
- 3 x 18GB 15K RPM Ultra160 SCSI in HW RAID5
- PERC 3/Di RAID Controller with 128MB battery backed cache
| Filesystem | Size | Used | Avail | Use% | Mounted on |
|---|---|---|---|---|---|
| /dev/sda5 | 30G | 1.2G | 27G | 4% | / |
| /dev/sda1 | 76M | 9.2M | 62M | 13% | /boot |
| /dev/sda2 | 1.4G | 59M | 1.3G | 5% | /var |
The ext3 filesystem has three different journaling modes. The default is ordered and is more conservative/safe then most other journaling filesystems. Supposedly the writeback mode is more akin to what other journaling filesystems such as reiserfs use. According to the man page for mount, "This is rumored to be the highest-throughput option". We plan to dispel the rumor, maybe we should submit a patch for the man page when we are done.
We tested ext3 in both ordered and writeback modes.
We've heard that the notail option of reiserfs can improve performance, especially with small files.
We tested reiserfs with and without the the notail option.
Software versions:
- kernel - 2.4.18-5
- PostMark 1.5c compiled with -O2
- Graphs generated with OpenOffice 1.0 Calc
