Comments on: How To Create an iSCSI SAN using Heartbeat, DRBD, and OCFS2 http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/ Wed, 07 Jan 2009 04:23:53 +0000 http://wordpress.org/?v=2.6.2 By: admin http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-163 admin Mon, 29 Dec 2008 15:17:56 +0000 http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-163 Yeah, I pulled the power cord during a write. No major bad things happened. How were you using FAT32 and NTFS as the filesystem though? I was using OCFS2 since it's an actual cluster file system. If you don't have a cluster-aware file system, bad things certainly will happen, including a lot of corruption. I'm not aware that NTFS would work for this, but I could be wrong. Yeah, I pulled the power cord during a write. No major bad things happened. How were you using FAT32 and NTFS as the filesystem though? I was using OCFS2 since it’s an actual cluster file system. If you don’t have a cluster-aware file system, bad things certainly will happen, including a lot of corruption. I’m not aware that NTFS would work for this, but I could be wrong.

]]> By: Anon http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-161 Anon Sun, 28 Dec 2008 23:23:18 +0000 http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-161 Did you test the failover when a write was occuring? Me and a friend of mine were testing a similar setup using windows/ubuntu clients to mount an iscsi drive shared between 2 drbd nodes. Provided we were using FAT32 and ntfs as the target filesystem, we noticed that if the primary drbd node was shutdown in the middle of a large write, we would get data corruption. We were also using the provided iscsi target daemon (tgt, or scsi-target-utils in centos 5.2) We were thinking this was either a problem with the iscsi daemon not commiting the writes to disk (as there was a large chunk of data missing in the file for when the failover occurred). Was there a specific reason you used ocfs2 as the filesystem? Thanks for the writeup! Did you test the failover when a write was occuring? Me and a friend of mine were testing a similar setup using windows/ubuntu clients to mount an iscsi drive shared between 2 drbd nodes. Provided we were using FAT32 and ntfs as the target filesystem, we noticed that if the primary drbd node was shutdown in the middle of a large write, we would get data corruption. We were also using the provided iscsi target daemon (tgt, or scsi-target-utils in centos 5.2)

We were thinking this was either a problem with the iscsi daemon not commiting the writes to disk (as there was a large chunk of data missing in the file for when the failover occurred). Was there a specific reason you used ocfs2 as the filesystem?

Thanks for the writeup!

]]> By: admin http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-10 admin Thu, 23 Oct 2008 21:45:59 +0000 http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-10 Sorry for the massive delay in a response. I wasn't receiving notifications when comments were posted. I'm sure it's too late for you, but for the sake of others... the setup was about $10,000 at the time, though I'm sure you could do it for less now. Each of the SAN servers was almost $4,000 when I bought them. I think you could use 1U servers now with RAID 1 and still easily get 1TB, which was my goal. The problem I had with the Dell SANs was the cost was about $7,000 for a simple iSCSI SAN that didn't provide any redundancy at all. I don't really think it'd be possible to just start with one server for the SAN portion. You'd have to later add DRBD and heartbeat, which, I believe could be done, but it would be pretty disruptive. Sorry for the massive delay in a response. I wasn’t receiving notifications when comments were posted. I’m sure it’s too late for you, but for the sake of others… the setup was about $10,000 at the time, though I’m sure you could do it for less now. Each of the SAN servers was almost $4,000 when I bought them. I think you could use 1U servers now with RAID 1 and still easily get 1TB, which was my goal.

The problem I had with the Dell SANs was the cost was about $7,000 for a simple iSCSI SAN that didn’t provide any redundancy at all.

I don’t really think it’d be possible to just start with one server for the SAN portion. You’d have to later add DRBD and heartbeat, which, I believe could be done, but it would be pretty disruptive.

]]> By: Marcus http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-9 Marcus Sun, 03 Aug 2008 00:37:00 +0000 http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-9 Oh, another question. Is it possible to start with just one 2950 and then expand to two without a huge interruption to service. Or does DRBD require configuration before creating the volumes/etc? Oh, another question. Is it possible to start with just one 2950 and then expand to two without a huge interruption to service. Or does DRBD require configuration before creating the volumes/etc?

]]> By: Marcus http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-8 Marcus Sun, 03 Aug 2008 00:15:00 +0000 http://www.creativeanvil.com/blog/2008/how-to-create-an-iscsi-san-using-heartbeat-drbd-and-ocfs2/#comment-8 Joe,<br/><br/>How much did the solution cost overall? I'm trying to virtualize 3 servers and I was thinking 4 dell 2950's 2 for the san, 2 for the VMWare installation (w/ha). The Dell MD3000i was looking promising but everyone the VMWare boards bashes the device. Its also about 15k loaded but doesn't provide TRUE redundancy as its just one device. Joe,

How much did the solution cost overall? I’m trying to virtualize 3 servers and I was thinking 4 dell 2950’s 2 for the san, 2 for the VMWare installation (w/ha). The Dell MD3000i was looking promising but everyone the VMWare boards bashes the device. Its also about 15k loaded but doesn’t provide TRUE redundancy as its just one device.

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