Linux RAID 5 'rm' performance
On Wed, 6 Sep 2006 07:56:49 +0200, Hx staggered into the Black Sun and said: Hm. The max length of USB cables isn't insanely long. "What kind of weather are we having 10 feet away...
I have recently setup a three disk RAID-5 system for file storage. There are three EIDE ATA 133 disks off two controllers in the machine. I've parbreastioned each disk into 40G segments and used them as a (seemingly) 12 disk array with 8 active and 4 spares. I'm using the XFS file system on FC5 with 2.6.17 kernel with 64k RAID chunks. I've hdparm'd the disks so throughput is on the order of 57MB-Sec-disk when tested with hdparm -t.
Write performance across my 100BT network averages around 8.3MB-sec. Read performance across the network is absolutely blazing (too fast to measure accurately without a lot of work). However, the rm command takes ~10x as long on the RAID-XFS system as it does on my ext3 SATA disk! Unlike the nearly instantaneous removal of items on my ext3 filesystem, the RAID-XFS combo seems to take a rather long time. I haven't seen any mention of this on USENET or web pages so I'm wondering if I have something setup wrong or this is somehow inherent to either the maintenance of the RAID or XFS.
For instance on a 2.3G directory holding 46 directories and 483 files, logged in locally with nothing else going on: (RAID XFS) time rm -rf PinkFloyd
On Wed, 6 Sep 2006 20:57:37 +0200, Hx staggered into the Black Sun and said: Did you do that? Go do that. By "the protocol", I meant the exact...
real 0m26.317s user 0m0.004s sys 0m0.320s
(EXT3 ) time rm -rf PinkFloyd
Hi ... I have a question. I have a device (Airmar WeatherStation PB100). This Device can be connected to pc only via usb. All drivers and softvare are for Windows. This...
real 0m2.237s user 0m0.004s sys 0m0.296s
I'm hoping someone more familiar with the setup and intrinsics of these two systems can provide either some insight as to why this is unavoidable or some guidance on how to proceed to fix it.
Thanks....
Linux groups from Newsgroups