Hi George,
The working transfers do just update 10 to 20Mb - very small turnover.
Unfortunately the two I need to mirror are from scratch - no baseline snapshot. The checkpoint restart occurring during the initialisation phase. Once the initialisation phase stalls further updates fail as the volume is not online (obviusly because the init failed).
I tried setting a once-a-day schedule at a particular time so it wouldn't trip over itself or other snapmirror operations to no avail.
As other volumes are updating with small update it made me wonder if it wasn't the router ipsec tunnel or firewall prematurely closing a connection for a large baseline transfer.
I'll attach the log & config when I get back into work.
Cheers, Raj.
On Sun, May 4, 2008 at 4:36 PM, George T Chen gtchen@yahoo-inc.com wrote:
Since you have one volume already transferring, then there's no network or firewall issue--any problem at that level would affect all volumes, not just a few.
A "Pending with restart checkpoint" appears you abort an ongoing transfer. Checkpoint occur every ?? megabytes and gives Ontap a place to restart instead of from scratch. It's hard to debug without more info, but I would start by:
- doing a snapmirror break on the volume (not just an abort)
- verify that there is a common baseline snapshot on both source and
destination 3) restart with a snapmirror resync command
Depending on step 2, you may be required to go to a snapmirror initialize.
What do the /etc/log/snapmirror and /etc/messages file say?
-gtchen
-----Original Message----- From: owner-toasters@mathworks.com
[mailto:owner-toasters@mathworks.com]
On Behalf Of Raj Patel Sent: Saturday, May 03, 2008 2:00 AM To: toasters@mathworks.com Subject: Oddball SnapMirror issue
We've got two FAS 270's in different cities. They're connected by a 10mb pipe with routers (running ipsec) & firewalls (checkpoint splat) seperating each datacenter.
The primary san is fine and runs all our prod volumes (7.0.5) which are mirrored to our secondary san (7.0.6).
Recently I had to recreate the mirror relationship for some volumes as they'd fallen far out of sync due to some firewall work.
What I am seeing is one volume is syncing fine, one has a small lag and two are stuck with a status of 'Pending with restart checkpoint' after I re-initialised the transfer.
snapmirror status -l shows this for one of the two that just don't get properly initialised
Source: 10.1.45.7:sqlprod01 Destination: adcsan1:sqlprod01_mirror Status: Pending with restart checkpoint Progress: 38376 KB State: Unknown Lag: - Mirror Timestamp: - Base Snapshot: - Current Transfer Type: Retry Current Transfer Error: volume is not online; cannot execute operation Contents: - Last Transfer Type: - Last Transfer Size: - Last Transfer Duration: - Last Transfer From: -
Our firewalls rules have been relaxed to allow free-flow between these devices (instead of just the SnapMirror ports) and the routers and circuit haven't changed at all between it working fine and not working now. The volume that is mirroring OK seems fine and still syncs fine - granted the updates are small whereas the three non-working volumes have to sync quite a lot of data.
I've tried deleting the mirrored volumes, recreating them, setting up the mirror relationship again (with a variety of scheduling and bandwidth throttling options) and doing a destination SAN reboot.
What are the best options to troubleshoot this or insuring a successful mirror ? Has anyone had issues with dropped or stalled SnapMirror baseline transfers via an IPSec tunnel or Firewall ?
Thanks in advance, Raj.
PS As an addendum it looks like it starts a transfer, stalls and from then on subsequent mirrors fail because its not online (ie the initialisation fails ?)
What I don't understand is why it just can't carry on with the initialisation regardless of the interruption by resuming the mirror operation ?