----- Original Message -----
From: "Daniel Sparrman" <Daniel.Sparrman AT EXIST DOT SE>
To: <ADSM-L AT VM.MARIST DOT EDU>
Sent: Monday, August 01, 2005 9:31 AM
Subject: Re: [ADSM-L] mirrorwritedb parallel - tried it?


*cut*

The security risk is mainly in a scenario were TSM writes to both of the
db volumes and crashes at the same time. This could result in a partial
write = database restore. To avoid this security issue when using parallel
writes, enable pageshadowing with "dbpageshadow yes" and "dbpageshadowfile
FILENAME". The pageshadowfile should preferable be placed on separate
disks from the TSM database volumes.

*cut*

If you use parallel writes and dbpageshadow, aren't you do sequential
writing again?
As far as i know, dbpageshadow is used with hardware-mirror in stead of
TSM-mirror, so there is still a sequential write possible.
So if you use parallel writes for a better performance and use dbpageshadow,
you still use sequential writes between the real db and the shadow and lose
the performance bennefit.

Regards,
Maurice