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Dell EqualLogic PS Query
Hi All
I'm fairly new to this so I apologise in advance :-)
We have a EqualLogic PS4110X, we have 2 SQL 2008 R2 servers running on Windows 2008 R2, one sitting in our live environment and one is sitting in dev. We want to be able to create one volume on the EqualLogic and present it to both servers. The idea is to back up our databases from our live environment to the volume on the EqualLogic and then restore from the same volume in development so we always have an updated copy of our databases in development.
I created a volume and gave both servers access, added them into ISCSI initiator on both machines and added them as an F:\ drive on both servers, the problem is when you create a file on one it doesn't appear on the other.
Is there a way to achieve what we want were trying to do?
Any help would be much appreciated.
Thanks,
Anonymous
5 Practitioner
5 Practitioner
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274.2K Posts
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July 30th, 2015 08:00
Hello Daniel,
This is a very common question. Your problem is that unlike a NAS, a SAN doesn't have any built in sharing features. You are connecting to the RAW device. When a server does that it believes it owns that volume exclusively. It does not periodically re-read or get notified by the other server when a new write occurs. Basic filesystems like NTFS, EXT4 are not cluster aware or capable file systems.
If you continue in the manner you will eventually corrupt the volume data. As either server can write to the same locations. If you shutdown the DEV server it will flush out it's view of the status of the drive. Which will not be up to date, potentially destroying data.
It's something I've seen in support for years. We call it "double mounting" a volume.
You have two choices. Purchase a cluster capable filesystem, which are extremely expensive or mount the volume to one server, and share it over the network to the other.
If this data is important to you, create a snapshot now, then POWER DOWN the Dev server. Do not do a shutdown as that will flush cache and write to the volume.
Regards,
Don