Steve

Does IBM have any plans for U2 to support SAN-level
synchronisation/mirroring, like other DBMS vendors do? 

For example: Oracle support EMC's Symetrix Remote Data Facility (SRDF)
for both Async and Sync modes (as well other vendors products).
http://www.emc.com/partnersalliances/partner_pages/remote_mirror_oracle.
jsp
http://www.oracle.com/technology/deploy/availability/htdocs/vendors_remo
te_mirror.html
Thanks.
 

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Stephen O'Neal
Sent: Thursday, 7 September 2006 4:30 AM
To: [email protected]
Subject: RE: [U2] rsync query - words of caution

All,

This is one that can have consequences.  Here are my words of caution...

Ian Stuart asked: how would this impact on the use of rsync on frequent
(every 10 minutes) replication?

The proposed snap/rsync cycle for a valid backup:
1) quiesce the database (Functional equivalents UDT DBPAUSE or UV
SUSPEND.FILES ON)
  1a) the sync call is initiated here to clear the disk buffers and
write to the disk subsystem
2) snap of the database (Functional equivalents Flash Copy, BCV, advfs,
etc.)
3) resume the database (Functional equivalents UDT DBRESUME or UV
SUSPEND.FILES OFF)
4) copy the snapped copy of the database via rsync to a remote system or
directory for backup
5) abandon the snapped copy (release the disk space) 

The above is valid for a replicating on an infrequent basis, say:
+ once in the evening for a backup and
+ maybe once in the middle of the day during a super slow time (like
lunch)

As comparative analysis of other shops, we observe most shops only doing

the evening backup snap, and never one in the middle of the day.

However, it is NOT RECOMMENDED for short term intervals at all.  We do
not 
see shops using it in short intervals.

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