topic snapmirror compression not working in 1 direction between sites in ONTAP Discussions

snapmirror compression not working in 1 direction between sites

canseeyou — Thu, 05 Jun 2025 07:12:08 GMT

We currently have FAS2020s in PROD and DR.

Due to bandwidth issues, we've been looking to enable compression on the snapmirrors. Both filers are running 7.3.2.

/etc/snapmirror.conf looks correct but we're seeing these messages and there's no compresssion when checking the logs.

Wed Jul 14 13:07:11 EDT [PRODSANA: snapmirror.src.multipath.connErr:error]:
SnapMirror is unable to set up a multipath/failover connection from prodmail1_pf_
data1 to DRSANA:prodmail1_pf_data1, SnapMirror is resorting to a single TCP
connection. Please ensure ports 10565 and 10566 are open in the firewall config
uration.

What's odd is that we created a test volume in DR and the snapmirror compression to PROD works fine. Traffic from

PROD <-> DR is going over the same vpn tunnel. The tunnel is fully open -- so the ports aren't being blocked.

From PROD -> DR, I've tried changing the snapmirror.conf to utilize the WSIZE and KBS values. But, that hasn't

seem to have done anything in terms of fixing the snapmirror compression to work.

The packet trace we ran -- what's odd is the WIN=value (presume these are the window sizes) for the frames look to be

different between the two files.

PROD WIN=7339776

DR WIN=1995456

Production has 10mbit of bandwidth that is only fully utilized when the snapmirrors are running (we've tried running a single snapmirror

when there is no traffic -- still same issue).

DR has a 100mbit connection.

Re: snapmirror compression not working in 1 direction between sites

dmorera — Thu, 15 Jul 2010 17:22:25 GMT

I ran into the same issue. Compression was working fine until we introduced Riverbed in the mix.

I check compression by running "snapmirror update <connection_name>" then "snapmirror status -l <connection_name>" while the update is going. If you don't see a compression rate, then compression is not configured correctly (been there, done that).

I throttled snapmirror updates, but it looks like you already tried that.

I'm sure you saw this KB, but jus in case... http://now.netapp.com/NOW/knowledge/docs/ontap/rel733/html/ontap/onlinebk/GUID-BB8BD542-B83F-43FD-A565-1FD20026B4C3.html

Re: snapmirror compression not working in 1 direction between sites

canseeyou — Thu, 15 Jul 2010 17:38:36 GMT

yeah, thanks -- have looked at that article multiple times.

I know our snapmirror.conf for compression is correct because we've done this for multiple clients. it's just at this particular client that the

issue has come up.

and, the reversal of DR -> PROD works with the compression.

the only thing I can think of is the bandwidth difference between the two sites (10mbit in prod, 100mbit in dr). other that than that, the fw hasn't show any issues

at all with the ipsec tunnel (normal snapmirrors work).

really at a loss especially with the dr->prod compression working.

Re: snapmirror compression not working in 1 direction between sites

dmorera — Thu, 15 Jul 2010 17:49:00 GMT

Check this out. I think this is your issue...

https://now.netapp.com/Knowledgebase/solutionarea.asp?id=kb56448

Re: snapmirror compression not working in 1 direction between sites

alapati — Thu, 15 Jul 2010 20:15:35 GMT

Compression will not work with multipath ICS is not setup correctly. Can you please post the snapmirror.conf entries on both source and destination (working and non-working).

thanks

Srinath

Re: snapmirror compression not working in 1 direction between sites

canseeyou — Thu, 15 Jul 2010 21:06:55 GMT

this what they look like from each filer. here's the top portions of the snapmirror.conf

*** NOT WORKING ***

#Regenerated by registry Fri Jun 11 12:13:08 GMT 2010
repsana=multi(NYSANA,DRSANA)
repsanb=multi(NYSANB,DRSANA)

repsanb:CIFS DRSANA:CIFS compression=enable 15 * * *

------------------------------------------------------------------
*** WORKING ***

#Regenerated by registry Mon Jul 12 18:55:10 GMT 2010
repsandr=multi(drsana,nysanb)
repsandr:compressiontest NYSANB:compressiontest compression=enable,restart=always - - - -