Snapshot Flakiness

Hi,
I have a Sun StorageTek 6140 array. Firmware version is 06.19.25.16. I am using CAM 6.0.1.11 on RHEL 5. What I mean when I say "flakiness" is sometimes taking snapshots and mapping the snapshots from the CLI works great, other times it doesn't. Sometimes when I try to create a snapshot for a volume, it tells me the volume doesn't exist. Other times when the snapshot is mapped to host, and I do a 'status' with the CLI for the snapshot, it doesn't return the LUN information. Sometimes when performing an operation such as creating a snapshot or mapping the snapshot or even deleting the snapshot, it will hang indefinitely at the command prompt. The command never returns and the operation never succeeds.
I have always had these problems since we've got the array in. I've had the problems with Solaris or Linux as the OS on the CAM server. The problems continue across different firmware versions and different versions of CAM. It always seems to be the same... Sometimes it works great, other times I'll catch a few when this happens. To clarify a bit, I have script that creates a bunch of snapshots and maps them to the backup host each night for my backup routine. It never has more than a couple snapshots going at one time. It seems completely random, one night all of them are perfect, the next not so perfect.
I recently switched to using cross-over cables for connection to the array from the CAM host to see if that would make a difference (instead of CAM and array both being on an Ethernet switch)... No luck, I get the same problems, just as frequently.
Anyone else have any issues like this?
Here is an example of a failure message when attempting to create a snapshot of a volume:
/opt/sun/cam/bin/sscs snapshoot -a goliath -v fms_html volume fms_html-snap
The specified volume could not be found. Unable to lookup the volume with wwn = 60:0A:0B:80:00:11:BB:60:00:00:56:97:45:FE:62:A8
That problem is pretty common, the other is the indefinite waiting for a command to return. When I say indefinite, that isn't actually true, I'm not sure how long I'd have to wait, but my script is set to timeout after 20 minutes of waiting.
--Marc

Hi !
I have had the same experience with a 6540 using snapshot, It does work but the snapshot luns do sometimes take a while to be picked up, We are using solaris 8, I do not why this happens ( so I'm not much hlp here, just to say we have the same issue and that it does work). If you're using solaris 10 it might be worth doing a devfsadm as part of the mapping, if you are scripting that is.
I know that when we unmap the luns we have to do a devfsadm -C otherwise we get un-owned luns left on the system.
Cheers
Garyg

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Why??? Simple snapshot can not refresh automatically, but can refresh manually.

Server 1 : Oracle 7.3.4 (as a Master site)
Server 2 : Oracle 7.3.4 (as a Snopshot site)
Client PC: SQL*Plus (Oracle 7.3.4 Client)
Step 1: on Client PC, start 2 SQL*Plus dialog Windows,
one(Window A) for <Server 1> , another(Window B) for <Server 2>;
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SQL>connect scott/tiger@Server1
SQL>CREATE SNAPSHOT LOG ON scott.dept ;
SQL>select * from dept;
DEPTNO DNAME LOC
10 AAAAAA AAAAA
20 BBBBBB AAAAA
30 CCCCCC AAAAA
Step 3: on <Window B> do:
SQL>connect scott/tiger@Server2
SQL>CREATE DATABASE LINK oracle USING 'Server1';
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start with sysdate NEXT SYSDATE+1/(24*60)
AS SELECT * FROM scott.dept@oracle;
-- refresh interval: 1 minute
SQL>select * from all_dept;
DEPTNO DNAME LOC
10 AAAAAA AAAAA
20 BBBBBB AAAAA
30 CCCCCC AAAAA
Step 4: on <Window A> do:
SQL>insert into dept values (50,'MMMMMM','NNNNN');
SQL>commit;
SQL>select * from dept;
DEPTNO DNAME LOC
10 AAAAAA AAAAA
20 BBBBBB AAAAA
30 CCCCCC AAAAA
50 MMMMMM NNNNN
<one or two minutes later ... ... >
Step 5: on <Window B> do:
SQL>select * from all_dept;
DEPTNO DNAME LOC
10 AAAAAA AAAAA
20 BBBBBB AAAAA
30 CCCCCC AAAAA
conclusion: Simple snapshot can not refresh automatically ???????
SQL>exec DBMS_SNAPSHOT.REFRESH( list => 'all_dept',method => 'F');
SQL>select * from all_dept;
DEPTNO DNAME LOC
10 AAAAAA AAAAA
20 BBBBBB AAAAA
30 CCCCCC AAAAA
50 MMMMMM NNNNN
conclusion:Simple snapshot can refresh manually.
How to solve this problem?????
Thank you very much
Zhang Ming-an

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