spreading partitions over multiple drives
Willem Jan Withagen
wjw at withagen.nl
Fri Sep 10 06:21:50 PDT 2004
Geert Hendrickx wrote:
>>Not for this usage.
>>>Fragmentation may be LESS of a problem with UFS, but a moving target
>>>like one big /usr (incl src, obj, ports) will get fragmented as well.
>>This is how you see it. I have not heard that there is any tool to help
>>I would not call this fragmentation. It is more like spreading the files
>>from one directory all over the disk.
>Ok but the effect is the same: constant movement of the head.
I would expect a bigger system to cache just about all file access
during 'make buildworld'.
Even when building things with -j 64 I can not get my dual-opteron 1Gb
system get without free pages.
And as such most files will only be read once, and object output will be
"slowly" synced on the disks.
Disk I/O rearly becomes the bottleneck, most of the time I'm missing raw
And I have everything on 1 large 200Gb disk.
>>>Splitting up partitions would reduce this fragmentation (as you are
>>>essentially defining some "super large blocks"), and may increase
>>>filesystem stability in case of crashes etc.
>>It might not affect stability but it increases the chances to fix a
>>problem in case of a crash.
>Yes I meant stability of the filesystem not of the running OS.
>Ok but the original question was about spreading partitions amongst
>multiple disks, not pro/con splitting partitions on one disk. :-)
My major problem with a lot of partitions has always been that one way
or antoher I outgrow a partition and then all of a sudden the logic
needs to be skewed for space reasons. Finaly disks start to grow to the
size where this becomes a moot point. 10Gb for /usr will last me until
we get to the next step of disk-sizes.
Having things on different spindles will of course be a major plus.
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