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tonyswu

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Hi,

We have a Kerio server running on Mac OS X Server 10.6.8. Hardware-wise it's an Xserve with 16GB of RAM, 3 x 1TB internal hard drives with RAID 5. The Kerio server itself has roughly 250 users, and the mail store itself occupies around 350GB of space. The Kerio data and system are on different partitions, but they are on the same RAID 5 volume.

Recently we've discovered that Kerio is taking an exceptionally long time to finish backing up. Even a differential backup on a weekday takes over 6 hours to complete. And when Kerio is attempting to back up, it brings down the whole server to the point I can't even SSH in. And as soon as the backup finishes, the server comes back in a snap. I drove to the data center during one of the backup, and found that generate a 100MB file on the system partition takes over 90 seconds. That's way too long. It seems Kerio backup simply occupies all the I/O on the hard drives. I initially think this is a hard drive issue, but I've used 3 different utilities to scan the hard drives, all came back clean without error.

I am wondering if anyone has this problem? I am contemplating on the possibility to move Kerio store onto an external drive, but for a mail server with 350GB of storage I ought to be able to keep everything in the same place.

[Updated on: Wed, 23 May 2012 20:25]

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InterHmai

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Is it a 2006 model xserve? The raid card from back then had a problem with raid5 that had really terrible read/write speeds.

Supposedly, you can avoid the problem by simply not using raid5. Re-doing the xserve raid storage would have been a nightmare on our mail server, so we ended up just getting an external raid storage box and cloning our mail storage to that.
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mwd

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Raid 5 is awful for Kerio anyway as Kerio deals with lots of small writes (Raid 5 sucks at this). I would always recommend Raid 10 for Kerio Connect.

It also sounds like you're using SATA drives which is another no no.
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MacLab

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SATA drives will be fine if you move to an external RAID 10. You can use eSATA with the Xserve and get good results.

MacLab, Inc.
Kerio Certified Partner, Reseller, Hosting Provider, Kerio Connect Certified.
http://maclaboratory.com
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dalenorman

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I have exactly the same hardware (perhaps a slightly more recent xserve, but otherwise very similar). I found that backing up to an external drive was far more manageable, but still very time consuming. i have two drobo's - a usb and a firewire 800. backing up to the usb drobo takes about 15 hours. to the firewire800 one takes about 5 hours. i do a full backup on sundays, and it does not take down the server while it's running.

perhaps a simple external drive for your backups is all you need. remember, raid5 takes a big hit when writing, not reading.

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tonyswu

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dalenorman wrote on Thu, 24 May 2012 07:00
I have exactly the same hardware (perhaps a slightly more recent xserve, but otherwise very similar). I found that backing up to an external drive was far more manageable, but still very time consuming. i have two drobo's - a usb and a firewire 800. backing up to the usb drobo takes about 15 hours. to the firewire800 one takes about 5 hours. i do a full backup on sundays, and it does not take down the server while it's running.

perhaps a simple external drive for your backups is all you need. remember, raid5 takes a big hit when writing, not reading.


That's the thing that I don't get, is that Kerio is set to backup to an external hard drive. In that case it really shouldn't take that much strain on the internal drives.

I am considering to move our Kerio storage to an external iSCSI RAID10 device. Perhaps that'll be better.
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MacLab

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tonyswu wrote on Fri, 25 May 2012 12:39

That's the thing that I don't get, is that Kerio is set to backup to an external hard drive. In that case it really shouldn't take that much strain on the internal drives.

I am considering to move our Kerio storage to an external iSCSI RAID10 device. Perhaps that'll be better.


Most likely your drives are tapped out as far as performance and the backup is putting it over the top.

MacLab, Inc.
Kerio Certified Partner, Reseller, Hosting Provider, Kerio Connect Certified.
http://maclaboratory.com
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