DB Logspace vs OS Swap

[Former Member]

Hi there,

i have a Test installation on a Server with little Hardware.

The Server has 4 Harddisks. I created 2 Raid 0 Volgroups.

Depending on this conditions i have to take one disadvantage.

I know recommended is:

RAID 10 for DB Log

RAID 5 for OS (Swapspace)

RAID 10 for DB Devspaces.

What will be better in Performance?

If i put the DB Log and the OS Swap on one RAID and the DB on the other,

or the OS Swap alone, and the DB LOG and the DB Devspaces together?

(Server has Minimum RAM, so i expect more or less swapping)

Regards

Manuel

[henrik_hempelmann]

Hi Manuel,

swapping will kill your performance, so reduce the size of the data cache (CACHE_SIZE) so that the system will not swap (during db access).

Put the data on one and the log on the other raid will speed up the writing speed of your transactions, but never put OS swap and data on the same I/O volume.

Regards,

henrik

[Former Member]

Hi Henrik,

> Hi Manuel,

>

> swapping will kill your performance, so reduce the

> size of the data cache (CACHE_SIZE) so that the

> system will not swap (during db access).

> Put the data on one and the log on the other raid

> will speed up the writing speed of your transactions,

> but never put OS swap and data on the same I/O

> volume.

Thats what i think, but is it better to put DB LOG and DATA on one disc,

and OS Swap alone,

or DB LOG and OS Swap on one, and DATA alone.

>

> Regards,

> henrik

Regards,

Manuel

[henrik_hempelmann]

> Hi Henrik,

> > Hi Manuel,

> >

> > Put the data on one and the log on the other raid

> > will speed up the writing speed of your

> transactions,

> > but never put OS swap and data on the same I/O

> > volume.

> Thats what i think, but is it better to put DB LOG

> and DATA on one disc,

> and OS Swap alone,

> or DB LOG and OS Swap on one, and DATA alone.

Manuel,

the answer is always the same: give it a try!

The situation is to complex and highly depending on your hardware configuration and the actual workload on the database. But I think it would be best to start with LOG and OS swap on the same disk, the changed data will be in memory before flushing log and data to independend drives.

henrik

[Former Member]

Hi Henrik

Thx for answering.

This should do it.

(marked as answerd).

Regards

Manuel