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cleverusername

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I'm trying to make KMS 6.7.0, patch 1 redundant.

I have recommended the following setup:

Primary:

    Windows 2008 guest OS on VMWare ESXi
    ViceVersa master for replication
    Replication data = c:\program files\kerio and D:\store
    Backups are scheduled to run to a network server


Secondary:

    Windows 2008 guest (clone of primary) on ESXi
    ViceVersa slave for replication
    IP address for primary is parked on a second vNIC in this guest (enabled upon primary fail)
    KMS services are OFF (manual svc start on primary fail)


Both ESXi hosts are in the same data center, and share redundant connections on two GB switches, so throughput is of minor concern (in other words, I'm not trying to replicate across a WAN).

Is anyone successfully running a high-availability KMS deployment that could share what products are being used to make it redundant?


The replication concept above works in the "lab" (test VM's), but it's a bit slow. I am looking for a product that would offer extremely fast replication.

I am also curious about any pitfalls that may occur as a result of KMS data replication vs. replicating the entire server.

Other methodologies are welcome! Smile

Thanks!
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cleverusername

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sjourney

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We are also looking for a replication solution. Looking into delta copy and DFS replication. 500 GB store...
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Nixs

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Here is a possible option;
http://www.visionsolutions.com/Downloads/resources/DT%20Shad owCaster.pdf
more;
http://www.visionsolutions.com/Downloads/resources/PS_DTAKE_ E.pdf

We've used their iSeries product for many years. We haven't used it for KMS, though.

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sjourney

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Well I tried DFS replication last night, it seemed to work well, got about half of the data replicated in 1 night... But then this am when the mail rush occurred the mail Que got backed up by 1500 emails. it seems to not want to process emails now when i turn it back on. very strange...

I guess this Nixs guy has very large pockets, those products are great but they cost about as much as the mail server itself. I just need a solution to mirror the data, i could care less about the full HA solution, i think my users could be down long enough for someone to change an IP address or 2 and start a service...

It is a shame Kerio has not stepped up the plate on this issue. I have called support on this before, i think there response was "do a backup every night to the backup server, then try to script KMSrecover to do a full restore biased on receiving the email saying the backup was done. yea right...

[Updated on: Tue, 23 June 2009 18:17]

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coolhandluq

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It's not a cheap feature you're looking for sjourney, that's just the way it is. VSphere has a new "constant availability" solution that may be worth it for you to look into, but of course VSphere costs cash money.

Here's what I do. I have two Kerio VM's. The 2nd or backup VM just has an up to date base installation of Kerio. It has the configuration backup of the good VM updated every night. I keep my mailstore on a separate LUN on the SAN from the VM's. In the event of a total failure of the first VM I map the mailstore LUN as drive on the 2nd VM, import the Kerio config from the nightly backup, start the mailserver, and point DNS to the new mailserver. I have tested this and I can do it in less than 10 minutes. This is an acceptable level of downtime for my company in the case of an unrecoverable VM.

The only thing I don't have here is two realtime copies of the mailstore. That is a level of risk I can take, as we have a very nice SAN that provides reliability. And of course nightly mailstore backups.
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sjourney

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We have Vsphere, or at lest the upgrade rights.. Kerio is not a VM in our environment, the Disk I/O would bring our SAN to its knees, we have 700 OUTLOOK users... Kind of need that perfomance for the other 80+ VM's.

I don't know what kind of SAN you have but if you just have your mail store on a RDM LUN, do you really have a DR copy... No, sounds like you have a backup VM ready to go, but what would happen if you lost the SAN, or your data center...

I was just joking with that Nixs guy, he works for the same company as me... We could afford double take, it would just be nice to have a solution that didn't cost thousands of dollars for once...

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coolhandluq

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We do have a DR copy of the mailstore. The nightly backup is replicated to another of our remote sites. We are a SMB with a distributed site model though, so our central datacenter is a closet. We're not of the size to spend lots of money on redundancy yet.

In regards to disk I/O, the vsphere numbers look pretty good but I don't have the capacity to test them myself. VMWare is saying that they can do 3x the IOPs than Visa uses now, but I guess if your SAN can't handle it then it's a no go. Most of our employees are only occasional users (think nurses), so our active connection count is very low in comparison to our mailbox count. We may have 300 mailboxes accessed a day, but only average 50 KOFF connections.
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sjourney

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U R Lucky. Kerio would be a VM if we had those kind of users...

[Updated on: Tue, 23 June 2009 20:29]

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sjourney

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I am going to try DFS again, this time with a replication schedule, until it gets a full rep in. then i will try removing the schedule...

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Nixs

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This is and idea "in the works" so to speak.

What if you had your e-mail deliver to TWO locations at the same time? You could do this several ways. The best would be to have Kerio send a copy to another location so that you get webmail sends, and internal sends.

So you have this e-mail queuing up on a separate box doing SMTP MTA but not delivering. Each night, after a good backup, you purge this MTA. If you ever do need to get these e-mails in a DR scenario, you let it deliver to your restored KMS box.

That would handle e-mail, but not other items such as calendar, notes, tasks, and so on.

Another option might be Continuous data protection. Veritas offers this as an option. http://www.symantec.com/business/netbackup-realtime-protecti on This use to be more like hourly backups, however it looks like it is now more like Double Take.

If I recall correctly, Double Take can do bit change copies of files so you don't have to copy the entire file every change, only those things that have changed. I don't know if Symantec offers this. Perhaps with the way KMS works, having many many small files, this is not a concern.


It would be nice if KMS used a real database, like MSSQL, which offers it's own replication capabilities and doesn't have the issues with fragmentation, minimum block size, and large quantity of files that exist in a raw file based system. Maybe then we could get true indexing.






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