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cbice

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We are currently experiencing "quirks" with using SAN Servers to store our mail. We are using the latest Kerio Mail Server on a RedHat Linux Enterprise 4 Update 2 box. We have mounted the store directories:

/home/kerio/mailserver/store/mail/domian.com

to a SAN Server using CIFS mounts. We need the ability to do this to allow for the massive amounts of email our users have 1TB. It seems to work ok, exept we get continuos errors in the erros log that say the following:

[17/Apr/2006 09:27:32] mail_folder.cpp: Index error in folder ~user<_at_>domain.com/INBOX: Cannot open database
[17/Apr/2006 09:27:33] mail_folder.cpp: Index error in folder ~user<_at_>domain.com/INBOX: The database file is locked

It writes one of those errors about every 2 seconds for random users. Also we have noticed that when you search using KOC, you never return any search results, as well as searching mail using Webmail.

I have talked with kerio and they say this is not supported.. so we will live with the issues for now, but will this ever be supported.. and out of curiosity, why would this be an issue?
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Kerio_jthomas

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Essentially KMS won't work well with any drive technology that wants to store the information remotely and retrieve it over a network connections.

This means remote SMB drives, NFS drives, SCSI over TCP/IP, and anything that runs over a packet-based network.

Latency is one large problem. Even at 1ms latency, this is 100 times slower than having a local disk. Another problem is file locking and writing. It's hard to know if you have a correct lock on a file when drive is external.

In short, KMS isn't designed for it. Needless to say we want to include quality NAS/SAN support in later releases =)

Joshua Thomas
Technical Support Manager
2350 Mission College Blvd, Suite 400
Santa Clara, CA 95054
Phone: (408) 496-4500
Fax: (408) 496-6902
http://www.kerio.com/support.html

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the_creative_partnership

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I assume that this does not apply to direct attached Fibre Channel storage (or through an FC switch)?

Would it apply to a SAN filesystem such as ADIC's StorNext whereby the storage is accessed over Fibre Channel but is subject to control by meta-data controllers (dedicated gigabit meta-data network)?

Cheers
Dan
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jshaw541

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pingu wrote on Tue, 25 April 2006 05:52

I assume that this does not apply to direct attached Fibre Channel storage (or through an FC switch)?



It *could*. As Joshua seems to be indicating, this is not a bandwidth issue, but a latency issue. It's conceivable that even with a direct-attached FC unit, you could experience "significant" latency of.

I haven't "pinged" our FC fabric recently, but I'd be curious if others have and what values they've seen.

Kerio MailServer 6.7.1 w/AD
Windows Server 2003 SP 1
Dell PowerEdge 2850 (Dual Xeon 3.2ghz and 2 GB RAM)
~1300 users
~1000+ concurrent IMAPS connections
iPhone users
Outlook 2007 KOFF users
Apple iCal 10.5/10.6 users
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Kerio_jthomas

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The only direct experience we have with Fiber Channel are the Apple XRAID systems.

While working correctly most of the time, we have had rare unreproducible access errors reported by some of our customers. Our development team is working with these customers to determine what the problem is. We still can not reproduce these problems.

I do not know about other Fiber Channel systems.

Any storage media which is directly connected to the system and accessible as a physical drive, should work well. This includes IDE, SCSI, and RAID drive combinations. I would recommend against USB attached media.

Hope this helps,
Joshua

Joshua Thomas
Technical Support Manager
2350 Mission College Blvd, Suite 400
Santa Clara, CA 95054
Phone: (408) 496-4500
Fax: (408) 496-6902
http://www.kerio.com/support.html

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jshaw541

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Joshua,

Do you have any idea what kinds of latencies you see on your FC gear? Even ballpark figures. Are you seeing >1ms? >10ms?

Kerio MailServer 6.7.1 w/AD
Windows Server 2003 SP 1
Dell PowerEdge 2850 (Dual Xeon 3.2ghz and 2 GB RAM)
~1300 users
~1000+ concurrent IMAPS connections
iPhone users
Outlook 2007 KOFF users
Apple iCal 10.5/10.6 users
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Kerio_jthomas

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jshaw541 wrote on Tue, 25 April 2006 09:47

Joshua,

Do you have any idea what kinds of latencies you see on your FC gear? Even ballpark figures. Are you seeing >1ms? >10ms?


No idea. I'm not involved in that testing directly.

Joshua Thomas
Technical Support Manager
2350 Mission College Blvd, Suite 400
Santa Clara, CA 95054
Phone: (408) 496-4500
Fax: (408) 496-6902
http://www.kerio.com/support.html

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dcsf

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It would've been nice to have had this information documented somewhere as I have not found this posted anywhere other than within this thread prior to deploying our server less than two weeks ago!

Actually, I even asked for information on placing the mail store on an Xserve RAID in the following thread:

http://forums.kerio.com/index.php?t=msg&th=8516&S=48 21c217e397beaa7370671d7b4ca466

That said, I'm under the assumption that I should move the mail store from the Xserve RAID over to the internal storage of the Xserve G5 as I am experiencing some issues. I currently have backups going to a SoftRAID mirror (drives 2 & 3). I'll reverse the setup and have the mail store on the mirror and the backup going to the Xserve RAID...

Please confirm if it is ok to locate the backups (using KMS' backup function) to an Xserve RAID.

Also, can someone from Kerio let us know what sort of issues are happening with those customers that the development team is working with? I'm wondering if the IMAP issues (posted in another thread) I'm experiencing is a result of the mail store location. I'm also experiencing the odd email not appearing in the inbox using Exchange accounts from multiple computers connecting to the same account concurrently (an email will appear in the inbox on one system, but may not on the other system).

Thanks.
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the_creative_partnership

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The reason I asked initially is that we are currently planning and installation for approx 70 users. As mail is a business critical app for us, uptime is obviously of the highest importance. We plan to run KMS on an Xserve DP with another Xserve for failover. We plan to use IP failover to ensure that there is always a server available to the users.

The debate is as to which of two strategies to use...

1) We have an Xyratex Kashi 4200 (Dual Active-Active Infortrend controllers) which we would direct attach to both hosts via a fibre channel switch and striped at RAID5. The mailstore and all necessary config files would be hosted on this. Server A would mount this on startup and provide primary mail service. Server B would be set to not mount this initially, only mounting it after a failover had been initiated.

2) No external storage would be used. Both servers A & B would be spec'd with sufficient storage for the mailstore (probably on a hardware RAID card, RAID1). The mailstore and all config files would then be sync'd (RSync or similar) on a nightly basis.

Does anyone have any opinions/tips/warnings about either of these scenarios? We prefer the idea of plan 1 as it means we do not have to worry about syncing the mailstore and configs or about them being 24 hours out of sync. But I am concerned that KMS may have issues with the FC storage...
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nhoague

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Has anyone had experience running Kerio Connect on an external storage? We are contemplating moving our store to an iSCSI device and wondering if it will work! We have tried mounting a NAS as CIFS and that does not work. FYI, we use Ubuntu server as our platform.

Thanks
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BLTomato

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We had our store on an Apple XRaid via direct Fiber channel for a long time and didn't have the greatest time with it. We experienced a lot of index.fld corruption (Like daily) when we used it with 6.X. Talking to Kerio Tech Support about it revealed that Apple XRaids just weren't fast enough to really keep up well with kerio and 150+ users.

We moved to a Xyratec with 10k SAS on the same Xserve and that improved it a bit. Altho going to 7 seemed to kill 95% of the corruption issues we were seeing. But we currently run 7.1 on a single XServe with that Xyratec and are happy with it (But I don't recommend buying Xyratec, we've seen some pretty bad corruption issues with others here that just do data storage and have to Disk Warrior them every month to avoid disasters.)
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nhoague

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Well update, I think it may have been an issue with the NAS box I was using. I setup a smb share via cifs to another linux host and Connect is able to use that as an external store with no errors, and performance is quite good. We are thinking about an iSCSI device with dual nics bonded, so hopefully upwards of 2 GB. We are going to be pushing 500+ users, and Im trying to figure a way to expand the storage dynamically. Nice to know it may be doable!
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renefn

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Just my 2 cents... I have recently moved our Kerio installation from a Windows Server 2003 installation on bare metal to a VMware ESX solution, running on the same hardware but with the VM running on an EqualLogic PS4000XV (16 15K SAS disks in RAID50) and a separate LUN for the messagestore, mounted with iSCSI inside Windows Server 2003.

The server is a Dell PowerEdge 2900 III with dual Quad-core processors and 16 GB RAM. Before the change the messagestore was running on local disks in a 4 drive RAID10 (15K SAS).

I haven't seen any issues at all and in fact it seems like performance has improved. I'm basing this on the speed of the webmail.

Regards,
Rene Frej Nielsen
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nhoague

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Ok that sounds pretty killer. I have run into another problem. While trying to cluster linux servers for HA, is it possible to have multiple Linux servers share the same store mount? Seems like Connect starts and mail passes, but very intermittent. I also end up with errors like this: [30/Aug/2010 15:44:03] ClientStatisticsDb.cpp: ClientStatisticsDb::createDatabase() - SQLite error: code 1, error SQLITE_ERROR[1]: no such table: main.user

I have two machines setup identically except for IP of course. They are both mounting to the same external share, and using the same mailserver.cfg and users.cfg file. The user accounts work, and the store gets modified when either machine accesses it, but doesn't seem to work.

Any ideas?
renefn

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I can't help you with the clustering... But from what I've read then Kerio really does not like sharing it's files with anyone, so I would only let one instance touch the files. We're protecting our setup by using ESX, so if we have a host failing then we'll just launch the Kerio VM (our own Windows Server 2003 install, not the Kerio Appliance) on another host.

If our EqualLogic fails, which it shouldn't according to Dell Wink, then we're actually replicating all data to another EqualLogic in another building, so I think we're pretty safe.

Regards,
Rene Frej Nielsen
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