Re: [Bacula-users] Quantum Scalar i500 slow write speed
2010-08-05 07:48:59
ekke85 wrote:
> The spooling attribute was not enabled, I have enabled it now. This is what I
> get writing to disk and then also writing that file to tape with tar:
Tape speed testing while writing a repetitive file is useless as
hardware compression makes it go a lot faster than natually.
For tape tests use /dev/random
NFS is a dreadful protocol and usually very slow (highly inefficient).
If you were streaming off the netapp at 22MB/s then you are doing well.
There are mount parameter you can apply to NFS to speed things up, we
well as moving to 9000 byte packets on a Gb network (don't do this in a
mixed speed environment, there are always problems)
Concentrate on getting the spooling working well - if you are using
anything higher than LTO2 your spool area will have to be a dedicated
striped disk array (or a SLC SSD) as LTO3 and onwards can easily outrun
a single hard drive's ability to stream data (if the drive has to do any
seeking, forget it....)
Bottlenecks appear all over the place with high speed tape. The only way
to find them is to test every component for throughput and latency as
well as testing the complete chain.
Don't forget to test the source speed of /dev/zero and /dev/random -
check throughputs when piping to /dev/zero. Ditto for despooling area.
If the tape speed is anywhere near approaching these speeds then your
results will be distorted.
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- [Bacula-users] Quantum Scalar i500 slow write speed, ekke85
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Thomas Mueller
- [Bacula-users] Quantum Scalar i500 slow write speed, ekke85
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Thomas Mueller
- Re: [Bacula-users] Quantum Scalar i500 slow write speed,
Alan Brown <=
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Henry Yen
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, John Drescher
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Henry Yen
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Christian Gaul
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Henry Yen
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Christian Gaul
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Paul Mather
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Henry Yen
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Christian Gaul
- Re: [Bacula-users] Quantum Scalar i500 slow write speed, Paul Mather
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