Thanks Dave,
After endless discussions with various people we understand that PPRC will
propogate partially written pages to both mirrors. Therefore like you, we
have decided to recommend TSM mirroring to the customer.
Richard Bates
Storage Specialist
ITS - SB - Enterprise Consultancy Services
==========================================
Voice : 00 44 (0) 1926 462298 (HICOM : 662298) (MOBEX : 270798)
[EMAIL PROTECTED]
"Frost, Dave" <[EMAIL PROTECTED]> on 12-06-2001 11:50:54
Please respond to "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
cc:
Subject: Re: tsm mirroring vs pprc
Richard,
"BTDTGTTS"
We are running tsm using san attached emc for all disk storage. On initial
setup of the emc, we decided to stop using log/db mirroring, and use the
emc
mirroring instead.
Soon afterwards, we had 2 instances where we could not restart the server.
Both times the server failed to restart because of an inconsistency in the
db log file. The emc mirroring had faithfully replicated the
inconsistency,
of course. In each case, the database had to be restored. Given a 35 GB
database, a restore can take about 2.5 hours.
IBM said that they "strongly recommend tsm mirroring", preferably with
verification.
So do we, now.
regards
-=Dave=-
-----Original Message-----
From: Richard Bates [mailto:[EMAIL PROTECTED]]
Sent: 08 June 2001 12:25
To: [EMAIL PROTECTED]
Subject: tsm mirroring vs pprc
Folks,
Customer site: TSM running on AIX. 2 x IBM Enterprise Storage Server, one
per data centre. SAN connecting it all together.
Problem: I've seen and read all the posts about TSM mirroring vs AIX
mirroring vs RAID mirroring. I understand the probem with partial page
writes and prefer TSM mirroring. We had planned to implement TSM mirroring
with a copy of the database and recovery log on IBM ESS in both of the data
centres.
However company strategy says that *all* mirroring must be done via PPRC.
Does anyone have any experience with PPRC? Can it cope with partial page
writes? Am I safer to use TSM mirroring?
Regards
Richard.
Richard Bates
Storage Specialist
ITS - SB - Enterprise Consultancy Services
==========================================
Voice : 00 44 (0) 1926 462298 (HICOM : 662298) (MOBEX : 270798)
[EMAIL PROTECTED]
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