topic Re: How to enable compression in snapmirror.conf in ONTAP Discussions

How to enable compression in snapmirror.conf

roch_norwa — Thu, 05 Jun 2025 07:19:19 GMT

Hi guys,

I read that compression mechanism for snapmirror comes with ontap 7.3.2

I tried to enable it, but with no luck.

According to documentation I edited snapmirror.conf on destination filer like this:

conection1=multi(netapp1,netapp2)
conection1:vol1 netapp2:vol1_rep kbs=5120,compression=enable * * * *

After that i'm getting error: Current Transfer Error: transfer from source not possible; snapmirror may be misconfigured, the source volume may be busy or unavailable.

My goal is to enable snapmirror from netapp1 filer (vol1) to netapp2 filer (vol1_rep) with 5120 kbs restriction on bandwidth, compression=enable and * * * * schedule.

Does anyone know how the snapmirror.conf should look like for this configuration?

Do i have to edit it on destination or source filer ?

Please help.

Roch

Re: How to enable compression in snapmirror.conf

tatlee — Wed, 20 Jan 2010 06:03:28 GMT

Hi Roch, see if this is a syntax error.

kbs=kbs

Maximum transfer speed, in kilobytes per second, that Data ONTAP can use to transfer data.

The kbs and restart arguments are expressed as a comma-separated list of name=value pairs, with no spaces. For example:kbs=2000,restart=always

If not using restart option, t

ry remove the comma after kbs=5120 and add the space.

Regards,

Terrence

Re: How to enable compression in snapmirror.conf

__frostbyte_9045 — Wed, 20 Jan 2010 14:24:56 GMT

See my conf below. You will see some that are compressed and some that aren't.

#Regenerated by registry Wed Aug 13 17:25:37 GMT 2008

# Min 0-59 or reoccuring /5 = evey 5 min

# Hour 0-23

# Day of Month 1-31

# Day of Week 0-7

starbuck_filer2=multi (starbuck,filer2)

apollo_filer2=multi (apollo,filer2)

starbuck_filer2:dfs_shares filer2:dfs_shares compression=enable 5 * * *

starbuck_filer2:users filer2:users compression=enable 10 * * *

starbuck_filer2:dmzsvrs filer2:dmzsvrs compression=enable 15 * * *

starbuck_filer2:assesspro filer2:assesspro compression=enable 20 * * *

apollo_filer2:tier1apps filer2:tier1apps compression=enable 25 * * *

apollo_filer2:dmzsharepoint filer2:dmzsharepoint compression=enable 30 * * *

starbuck_filer2:tier2apps filer2:tier2apps compression=enable 35 * * *

starbuck_filer2:tier3apps filer2:tier3apps compression=enable 40 * * *

starbuck:sqlbkup_t1 filer2:sqlbkup_t1 - 1,15,30,45 * * *

starbuck:sqlbkup_t2 filer2:sqlbkup_t2 - 5,20,35,50 * * *

For replication throttling, I use the system option since I am primarily concerned with wan utalization. The following options are used. Combine this with staggered volume replication and we make out ok.

replication.throttle.enable on
replication.throttle.incoming.max_kbs 3500
replication.throttle.outgoing.max_kbs 3500

Re: How to enable compression in snapmirror.conf

ogra — Thu, 21 Jan 2010 03:26:51 GMT

Hi Roch,

Simply remember that SnapMirror is a pull technology.

Hence, to define any relationship you need to define it on the destination and not the source.

This means snapmirror.conf file needs to be created on the destination and not the source.

Now for the syntax part, you can try using the FilerView for creating the relationship, if you are facing syntax error.

For a restricted throttle option of 5120kbps, you can implement is at either individual relation level or system level.

Above, David has highlighted it at the system level.

Keep us posted !

-Bakshana

Re: How to enable compression in snapmirror.conf

BrendonHiggins — Thu, 21 Jan 2010 12:27:13 GMT

What sort of compression rates are you seeing?

Bren

Re: How to enable compression in snapmirror.conf

__frostbyte_9045 — Thu, 21 Jan 2010 12:52:36 GMT

This is an area where thus far, reporting seems to be lacking. You can only see the compression ratio for current snapmirrors. Since we do them every hour, with a new volume every 5 minuites, it's kinda hard to keep tabs on it. I guess I could schedule an rsh script and dump that into text. <Rant Over>

What I have seen in the past is around 1.5 to 1. Most volumes are already de-duped and either have 8 VMs in them or are CIFS volumes.

Re: How to enable compression in snapmirror.conf

alapati — Thu, 21 Jan 2010 13:10:30 GMT

Compression ratios are also logged in the SnapMirror log file after the transfer is completed. Therefore you have two ways:

1. During the transfer, a long listing of SnapMirror status command will report a ratio

2. After the completion of the transfer, check the /etc/log/snapmirror file.

Also, check out the SnapMirror Async tech report (page 27).

SnapMirror Async Overview and Best Practices Guide
http://www.netapp.com/us/library/technical-reports/tr-3446.html

Srinath

Re: How to enable compression in snapmirror.conf

__frostbyte_9045 — Thu, 21 Jan 2010 13:24:46 GMT

Nice. Looking through the log, at transfers of a meg or more, I'm seeing 1.4:1 up to 6.1:1. Many are in the 4.0:1 range and I'd have to guess that is the overall average, at least for last night.

So, it's a free license! The only penalty is CPU overhead. If you need it, turn it on for everything, examin the logs, then turn it back off for volumes that don't seem to benefit from it. Since we have a cluster, we have extra CPU (allowing room for failover). I guess it could be something to keep an eye on if we are in a failover mode for an extended period.

Re: How to enable compression in snapmirror.conf

truemichael — Thu, 11 Feb 2010 17:14:29 GMT

David,

Would you mind elaborating on the below lines in your conf file?

starbuck_filer2=multi (starbuck,filer2)

apollo_filer2=multi (apollo,filer2)

I've read conflicting threads noting that these lines are required for the compression option. Thanks in advance!

Re: How to enable compression in snapmirror.conf

__frostbyte_9045 — Thu, 11 Feb 2010 17:26:19 GMT

I too had questions regarding these lines as they show up in the latest documentation but are not explained. When I called support, they didn't even know that you could compress a snapmirror transmission. I guess all of the sales hype over dedupe and how that could enable a form of compression prior to replication led everyone to believe that there wasn't anything else needed.

If you are not using compression, they are not needed. If you are using using compression, you have to define a relationship. This seems stupid to me because you define the relationship in each line of the config file. I suspect that this line is going to facilitate some other functionality in the future but who knows, it could have been some poor coding.

starbuck_filer2=multi (starbuck, filer2)

The first half of the statement "starbuck_filer2" is the connection string. I used "source_destination" for my naming scheme.

The last part of the statement (starbuck,filer2) are your source and destination filers.

I have not seen or had explained to me what the purpose of "multi" is in the statement, nor have I found any other choices. Perhaps it enables one to many replication targets. But if this is the case, of what benefit would it be to have a single option, unless there was a performance gain (doubtful). Security doen't make sense because both this statement and the actual schedule are in the same file. Oh well.

If you find someone who can enable the compression with out these statements, please, let me know. However, when I set it up using 7.3.2, it wouldn't work with out.

Re: How to enable compression in snapmirror.conf

__frostbyte_9045 — Thu, 11 Feb 2010 17:28:21 GMT

Re:

This means snapmirror.conf file needs to be created on the destination and not the source.

Like several other files, I find it easiest to make one file for your enviornment and put it on all filers. If the relationship line isn't applicable to the current filer, it will ignore it.

This makes it a bit easier to keep up with versioning and forgetting something somewhere.

Re: How to enable compression in snapmirror.conf

adamfox — Thu, 11 Feb 2010 17:37:17 GMT

You do need to set up compression by creating a connection as you described above.

The purpose of the word "multi" is similar to multi-mode vifs. You can define multiple pairs to be used if you choose. This is used mostly for doing SnapMirror over FC, but it can work with Ethernet too.

There is a 'failover' mode as well which is like a single mode vif.

As far the support call, this was most likely an education issue on the Global Support side.

The best description I've found for connections in snapmirror.conf is the snapmirror.conf man page. It's in section 5 and it describes the connection lines pretty well, IMHO.

Hope this helps.

Re: How to enable compression in snapmirror.conf

truemichael — Thu, 11 Feb 2010 17:38:22 GMT

Actually I semi understood what the =multi switch impacted, but not specifically with compression. According to documentatrion, the =multi switch is used when defining multiple physical destinations (max two per source) for a given snapmirror relationship. If you feel my input is vague, that's because NetApp documentation is just as vague. 🙂 I appreciate the explanation very much....now onto compressing data. WOOHOO!

Re: How to enable compression in snapmirror.conf

alapati — Thu, 11 Feb 2010 18:24:44 GMT

Check the error messages on the destination as well. If you are trying to initialize, make sure the destination volume is restricted. Also, make sure permissions are defined (options snapmirror.access) to that the destination system can get the data from the source. You are correct in defining the .conf file on the destination system. Check the /etc/log/snapmirror file on the destination system.

Re: How to enable compression in snapmirror.conf

kannan_chandar — Thu, 07 Mar 2013 08:13:40 GMT

I too had the same problem. It got resolved after I put FQDN hostname in source filer field.