William,
It should be fairly easy to find the record size using DTrace. Take an
aggregation of the
the writes happening (aggregate on size for all the write(2) system calls).
This would give fair idea of the IO size pattern.
Does RRD4J have a record size mentioned ? Usually if it is a
database-application they have a record-size
option when the DB is created (based on my limited knowledge about DBs).
Thanks and regards,
Sanjeev.
PS : Here is a simple script which just aggregates on the write size and
executable name :
-- snip --
#!/usr/sbin/dtrace -s
syscall::write:entry
{
wsize = (size_t) arg2;
@write[wsize, execname] = count();
}
-- snip --
William Fretts-Saxton wrote:
> Unfortunately, I don't know the record size of the writes. Is it as simple
> as looking @ the size of a file, before and after a client request, and
> noting the difference in size? This is binary data, so I don't know if that
> makes a difference, but the average write size is a lot smaller than the file
> size.
>
> Should the recordsize be in place BEFORE data is written to the file system,
> or can it be changed after the fact? I might try a bunch of different
> settings for trial and error.
>
> The I/O is actually done by RRD4J, which is a round-robin database library.
> It is a Java version of 'rrdtool' which saves data into a binary format, but
> also "cleans up" the data according to its age, saving less of the older data
> as time goes on.
>
>
> This message posted from opensolaris.org
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Sun Microsystems India Pvt Ltd.
Tel: x27521 +91 80 669 27521
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