Edward,

we're using mirroring as well on big private volumes.

You will see performance advantages if you have a lot of reading processes
- they will be executed in parallel (especially on multiprocessor boxes).
In our point of view, there is no overhead. In our situation, mirroring
solved the disk bottleneck we had.

The documentation in the manual is good. Additionally, HP has CE internal
papers here in Germany describing short and to the point what to do in any
situation of H/W failure. If you are interested in please let me know.

During the move of data to the mirrord set you should wait before shutting
down the box until all members have been synchronized! This may take a
while.

For applications, mirroring is really transparent. If you're already
working with Private Volumes there is no difference in handling.

If you have more questions feel free to contact me directly.

Best regards, Andreas Schmidt, CSC Germany (back from vac.)






[log in to unmask] on 05/13/99 07:36:24 PM

Please respond to [log in to unmask]

To:   [log in to unmask]
cc:    (bcc: Andreas Schmidt/HI/CSC)
Subject:  Private Volumes and Mirror-XL




All:
I am looking to implement Mirroring in my environment which forcing me
to implement private volumes.I am on a 969 box running MPE ix 5.5 pp4. I
am trying to learn as much as I can about both to plan this
implementation wisely. Is anyone else mirroring or using private
volumes? If so, how is it going? Are there any "GOTHCHA'S" I should
start considering? What security issues have you had? What is the system
overhead (performance issues) with mirroring? What are the
administrative issues (or nightmares)? Was  applications set  a
challenge? These and any other things you think I should consider would
be appreciated.
Thanks Group
Edward Jordan
Computer Operations Manager
20th Century Plastics
205 S. Puente Street
Brea, Ca 92821
voice: 714.441.4500 x2431
fax   : 714.441.4536
email :[log in to unmask]