martin f krafft wrote: > I set up a Software RAID System previously. It contains four 120Gb > harddrives, 8 partitions on each, with the forth drive being used as > a spare:
[SNIP] > As you can see, the first is a simple RAID 1, all the others are > RAID 5. All have a chunk size of 32 and an ext3 filesystem (-b 4096 > -R stride=8). Only md5 has a chunks size of 4 and an ext3 filesystem > with blocksize 1k and stride=4 (because it is so small). > > Now, if I use bonnie++ on a dual 2GHz with 2Gb RAM on a reiserfs > partition on a 120Gb Maxtor IDE harddrive, I get the following > results: [SNIP] > If I use the same options on aforementioned RAID system (1GHz single > processor machine, 1Gb RAM and ext3), I get these results: [SNIP] > Eyeballing, there is a factor 4-8 of a difference. This can't be > mere processor power, can it? Does this mean that my RAID is > performing worse than crap? > > Does anyone have any clues, any suggestions for a better test, or > any improvements for my RAID system? Russell? The first thing I notice is that you compare two different filesystems: reiserfs and ext3. It is a known fact that reiserfs is in most workloads *much* faster than ext3. Redo your test with either ext3 on the 2GHz machine or reiserfs on the RAID5/1GHz machine. Next: How are your three (four) disks connected? Do they all have a seperate IDE channel or do some of them share one? Do all disks have DMA turned on? Compare the output of 'hdparm -vi /dev/hdX' from the 2GHz machine with the values from the 1GHz machine. Make them the same if they aren't. Next: Try with the defaults values for chunk size, algorithm and ext3 stride. How does it look now? Next: Use an external journal for ext3 that is located on a RAID1. Cheers, Juri -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
