Messages in this thread |  | | | Date | Wed, 29 Aug 2001 09:39:27 -0700 | | From | "Randy.Dunlap" <> | | Subject | Re: Journal FS Comparison on IOzone (was Netbench) |
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Andrew Theurer wrote: > > On Monday 27 August 2001 01:24 pm, Randy.Dunlap wrote: > > Hi, > > > > I am doing some similar FS comparisons, but using IOzone > > (www.iozone.org) instead of Netbench. > > > > Some preliminary (mostly raw) data are available at: > > http://www.osdlab.org/reports/journal_fs/ > > (updated today). > > > > I am using a Linux 2.4.7 on a 4-way VA Linux system. > > It has 4 GB of RAM, but I have limited it to 256 MB in > > accordance with IOzone run rules. > > > > However, I suspect that this causes IOzone to measure disk > > subsystem or PCI bus performance more than it does FS performance. > > Any comments on this? > > Randy, > > You are definitly exceeding what the kernel will cache and writing to disk on > some tests. I guess it depends on what is more important to you. I think > both are valid things to test, and you may want to try not limiting memory to > get just FS performace in memory for large files. However, writing to disk > is important, especially for things like bounce-buffer. Did you have himem > support in your kernel? If so, did you have a bounce-buffer elimination > patch as well?
Hi-
Sorry about the delay in responding.
I'm interested in filesystem performance. I'm not trying to document IDE vs. SCSI vs. FC performance/price tradeoffs, benefits, etc.
> Does the storage system/controller have a disk cache? What size?
Good questions, but I'm having trouble finding answers for them. (hence the delay in responding)
The FC host controller is a QLogic 2200. It is attached to an IBM FAStT controller/drive array -- one controller with 10 attached drives. I've been looking at the IBM FAStT OS console interface, but I can't see much cache info there. There is one item: cache/processor sizes: 88/40 MB
> Also, does IOzone default to num procs=num cpus? I didn't see any options in > your cmdline for num_procs.
No, IOzone doesn't default to num_processes = num_cpus. That's a command-line option that I didn't use, although I expect to do some testing with that option also.
Thanks for your comments.
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