Janek Kozicki wrote:
Hello,
Yes, I know that some levels give faster reading and slower writing, etc.
I want to talk here about a typical workstation usage: compiling
stuff (like kernel), editing openoffice docs, browsing web, reading
email (email: I have a webdir format, and in boost mailing list
directory I have 14000 files (posts), opening this directory takes
circa 10 seconds in sylpheed). Moreover, opening .pdf files, more
compiling of C++ stuff, etc...
In other words, like most systems, more reads than writes. And while
write can be (and usually are) cached and buffered, when you need the
next bit of data the program waits for it, far more user visible. If
this suggests tuning for acceptable write and max read speed, and
setting the readahead higher than default, then you have reached the
same conclusion as I did.
I have a remote backup system configured (with rsnapshot), which does
backups two times a day. So I'm not afraid to lose all my data due to
disc failure. I want absolute speed.
Currently I have Raid-0, because I was thinking that this one is
fastest. But I also don't need twice the capacity. I could use Raid-1
as well, if it was faster.
Due to recent discussion about Raid-10,f2 I'm getting worried that
Raid-0 is not the fastest solution, but instead a Raid-10,f2 is
faster.
So how really is it, which level gives maximum overall speed?
I would like to make a benchmark, but currently, technically, I'm not
able to. I'll be able to do it next month, and then - as a result of
this discussion - I will switch to other level and post here
benchmark results.
How does overall performance change with the number of available drives?
Perhaps Raid-0 is best for 2 drives, while Raid-10 is best for 3, 4
and more drives?
best regards
--
Bill Davidsen <davidsen@xxxxxxx>
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark
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