Wednesday, 3 January 2007

A quicker cp (Results)

I tested my cp script (which I called pcp ' parallel cp') against a NetApp NFS server from a Solaris client. The best results vs standard 'cp' was when the FS was mounted '-o forcedirectio'. Since forcedirectio is often used by DB hosts, and DB servers typically use very large files the performance of cp can be quite important. During my tests I saw roughly 100% improvement, i.e. it took 1/2 the time to copy a large file using 'pcp' vs standard 'cp' for a file of 2Gb.

Here are some graphed results which I took from the raw iostat.

Standard Solaris cp

Vs pcp using 1MB IO's and 8 dd 'threads'.

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