Consultor Eletrônico

Convert to Multi-Volume if Running on Striped Filesys? YES

Is it worthwhile to convert to a multi-volume database structure
even if you are using a striped file system? Yes. Here's why:

It reduces the amount of indirection taking place. When searching
for an address, if the file is small enough unix may be able to
find the address on the first attempt, which is direct i/o.

If the file is too large, unix may need to make one attempt
to find the address, and based on the the first address, a second
attempt to find the address using an offset from the first.
This is called indirection.

If you are on a striped file system, without going to multi volume
the database is still considered one large file to the operating
system. If you convert to multi volume, you are increasing the
chances of hitting an address on the first try because you are
working with several smaller extents, normally less than 200 meg.

Also, if you do not use a multi-volume structure then when adding data
the database grows in 64k chunks. This performance hit will be paid
by the client. By converting to multi volume, this overhead is
effectively taken off-line by pre-extending the database with the
extents.

Progress Software Technical Support Note # 14065