[Linux-cluster] Block Size

Stephen Nelson-Smith sanelson at gmail.com
Thu Feb 19 20:35:11 UTC 2009


I have a 1TB LUN on an EMC SAN, which I see in /proc/partitions as emcpowera.

Ultimately I will be sharing this between two, or three machines, but
at present only one is fibre attached.

I propose to create a GFS2 filesystem now, and use it with one machine
until it becomes necessary to share the LUN with the other machines.

The backups/storage engineer from my hostco recommends I use a
blocksize of 128kb to ensure there are no missed alignments on the SAN
that could degrade performance.  128kb sounds *huge* given that the
default is 4k.

Two questions:

Any problems with the recommended approach - ie mkfs.gfs2 first, worry
about clustering later?

Is mkfs.gfs2 -b 131072 really sane?



Stephen Nelson-Smith
Technical Director
Atalanta Systems Ltd

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