Some numbers for modern disk performance
Since I currently have a semi-test system floating around, I decided to collect some numbers on what sort of disk performance I can expect from a modern SATA-based system. The quick summary is that it's pretty good.
I'm only really interested in three numbers: streaming writes, streaming reads, and random IOs per second. Fortunately bonnie++ will give me those, along with a bunch of other numbers that I don't really care about.
My test system has two Seagate 7200.10 320GB SATA drives, identically partitioned, and all of the testing used a pair of identical (and otherwise empty) 58 Gb partitions.
|Single disk||60 Mb||73 Mb||171|
|Both disks at once||114 Mb||136 Mb||268|
|LVM on one disk||59 Mb||72 Mb||215|
|LVM on both disks, two bonnies||116 Mb||132 Mb||281|
|RAID-1, one bonnie||66 Mb||69 Mb||200|
|RAID-1, two bonnies||60 Mb||89 Mb||179|
|LVM on RAID-1, one bonnie||75 Mb||69 Mb||344|
|LVM on RAID-1, two bonnies||59 Mb||116 Mb||231|
(Disclaimer: I won't claim that these are scientific benchmarks, carefully statistically analyzed to make sure that they're valid; I don't have that much time and patience.)
All LVM partitions were using 32 Mb extents, which is the default on Fedora Core 5.
Some interesting things show up in these numbers: for example, note that using LVM apparently somehow improves your seek performance (assuming that bonnie is measuring this correctly). In general, LVM seems to at least not hurt compared to the alternative, and may even work better, which is reassuring since I'm setting up this system with LVM, having given in to the temptation.
Sidebar: the test system
The test system is an ASUS M2N4-SLI (running with
noapic) with an
Athlon 64 X2 4600+, 2G RAM, and the aforementioned Seagate SATA drives,
using the x86_64 Fedora Core 5 with the current set of updates.
bonnie++ was run with just '
-r 2048', so it used 4GB per instance.
The system was running a CPU cruncher per core, but was otherwise idle.