Does anyone have suggestions on how to lay out the filesystems in UNIX for DB2 in a large OLTP environment? We are going to have the following:

/db2home - home filesystem for all instances
/db2log_p - filesystem for primary logs
/db2log_s - filesystem for mirrored logs

Any other suggestions from experience? As filesystems can get corrupted, we are separating them out for reliability, and not performance reasons. The filesystems are all located on a SAN.

Thanks for the help.

Hi,

add

/db2dbcfg/db2instx/dbnamey

and create your dbs on /db2dbcfg.

Instead of a general /db2home for all instances, I recommend a database specific filesystem

/db2home/db2instx/dbnamey

for each of your databases. Same with logs.

Also, you may want to consider if separating each database's temp space would make sense.

Johann

Thanks!! This is exactly how I am doing it. Just curious - what is the rationale for separating temp space? Thanks.

Hi,

One of the rationale for seperating TempSpace is that it avoids sorts and all temperoary operations in the same area.

Hence it improves performance to a good degree.

HTH

Nitin

Hi,

another point is it becomes easier to tell why your filesystems or containers are getting full. If it is the temp space, it is probably enough to force an application, if it is data, you need to enlarge containers.

Johann

When I first read your response, I thought that when you said to separate out the "temp" space, I thought that you meant the /tmp operating system temp space. What you are really saying is to have a filesystem hold the userspace tablespaces for the database tables, and another filesystem hold the temporary tablespaces for the temporary tables (when they grow due to sort overflows, etc.). This makes sense in the case of separate disks. Does it buy me anything when I have a SAN on the back end and I am just allocating disk (from the same virtual pool of disk) for these tablespaces? If the tablespaces were on different RAID drives, I can see how the performance would improve. If the RAID drives were the same, I would not expect any improvement in performance. What are your thoughts. Thanks again.

Hi,

when your disks are represented by SAN, it is probably not so much a question about performance, but it is still a question about managability and ease of monitoring.

Johann