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Gyto
Posting Yak Master
144 Posts |
 Posted - 2012-01-16 : 11:08:29
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| Hi there,I will shortly be setting up a SQL cluster for the first time and I just wondered what the best disk setup would be?I have seen the following recommended:A: Quorum disk (1gb)B: MSDTC disk (1gb)C: Systems Databases (Data and Logs)D: User Databases (Data and Logs)This seems reasonable, but wouldn't it still be recommended to have the data and logs on separate drives? ...and if so would that apply for both the system and user databases? If you wanted them all on separate drives then that's going to be 6 drives which seems a bit overkill! Any thoughts?Also, is 1gb enough for the Quorum and MSDTC disks?Thanks,Matt |
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dinakar
Master Smack Fu Yak Hacker
2507 Posts |
Posted - 2012-01-16 : 12:39:24
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| At the minimum I would recommend:1 LUN for TempDB Data1 LUN for TempDB Logs1 LUN for userDB Data1 LUN for userDB Logssystem database data and logs can go on same LUN.By the way, you dont need to assign drive letters to all disks.. SQL Server supports mount points, so create a root volume (with a drive letter) and create mount points for the other LUNsDinakar Nethi************************Life is short. Enjoy it.************************http://weblogs.sqlteam.com/dinakar/ |
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Kristen
Test
22859 Posts |
Posted - 2012-01-16 : 13:51:38
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| ... and backups on a separate drive |
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Gyto
Posting Yak Master
144 Posts |
Posted - 2012-01-17 : 05:16:44
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| Thanks Dinakar - that's the sort of thing I was thinking, although I wasn't aware of the LUN principle so thanks for that - fortunately I have server administrators to set this bit up for me, I just need to tell them what I want ;o)The backups will taken to our central backup location, so I shouldn't need to worry too much about where the default location is. |
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Kristen
Test
22859 Posts |
Posted - 2012-01-17 : 06:38:19
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| I don't have experience of very large databases, but we backup to disk files (local-ish to the server) and then let the IT folk get those files onto Tape / offsite / etc.Never been happy with direct-to-tape systems for a number of reasons (happy to elaborate if you need me to) |
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Gyto
Posting Yak Master
144 Posts |
Posted - 2012-01-30 : 08:07:47
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| Thanks Kristen - that's the way we will be doing it, backups to disk initially that are then archived off onto Tape.One more additional question on this subject though...I was under the impression that in a cluster with 3+ nodes, all nodes would share the same LUN for their UserDB Data files and the same LUN for their UserDB Log files, and that they would all be able to access and read/write to them at the same time. Someone else has questioned this saying they weren't sure if more than 1 node could access the same LUN simultaneously, so they might need separate data/log file LUNs for each node...?I thought the whole idea was that they shared the exact same storage locations? Am I missing something here??Thanks |
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GilaMonster
Master Smack Fu Yak Hacker
4507 Posts |
Posted - 2012-01-30 : 08:45:18
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| LUNs are only used by one cluster node at a time. Whichever node the LUN is active for is the only one that can access it. So if you have three separate instances (assume they're running on different nodes and are in different cluster groups), each needs its own drive for its files.--Gail ShawSQL Server MVP |
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Gyto
Posting Yak Master
144 Posts |
Posted - 2012-01-30 : 09:11:49
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| Ok thanks Gail, that's very helpful. |
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Gyto
Posting Yak Master
144 Posts |
Posted - 2012-02-01 : 11:44:08
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| Right, apologies for going over this again, but I just want to double check I've got the right idea before I go too far....I am currently thinking at the following setup:1 (LUN/Disk?) Quorum (1gb)1 (LUN/Disk?) MSDTC (1gb)1 LUN Node1 Data (User & System DBs)1 LUN Node1 Logs (User & System DBs)1 LUN Node2 Data (User & System DBs)1 LUN Node2 Logs (User & System DBs)1 LUN Node1 TempDB Data1 LUN Node1 TempDB Logs1 LUN Node2 TempDB Data1 LUN Node2 TempDB LogsCould someone possibly just answer the following questions:1) Does each node have its own system databases or does the whole cluster share the same ones? (If they share they I will obviously only need 2 tempdb LUNs for the cluster rather than 4) 2) Aside from the tempdb, is it ok to put the other system databases on the same LUNs as the user db data/logs, or should I create separate LUNs for them?3) Do the Quorum and MSDTC have to be on their own physical disks or can they be on LUNs?4) Is 1Gb big enough for the Quorum and MSDTC LUNs/Disks?5) Both the Quorum and MSDTC serve the whole cluster, so only one of each is required regardless of the number of nodes?6) Can anyone see any other problems with this?Thanks all! |
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GilaMonster
Master Smack Fu Yak Hacker
4507 Posts |
Posted - 2012-02-01 : 12:41:42
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| Each instance has its own system databases, and they are on shared storage. Remember that a LUN is owned by one node at a time--Gail ShawSQL Server MVP |
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Gyto
Posting Yak Master
144 Posts |
Posted - 2012-02-02 : 06:52:11
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| Thanks Gail, so can you confirm if this is correct:In an active/passive environment, Each ACTIVE instance has its own system databases on the LUN(s) which it owns, then in the event of a failover the PASSIVE node simply takes ownership of these LUNs and effectively inherits the system databases contained on them (meaning the passive node does not have its own system databases to begin with?)Therefore, all you'd need in a 2-node (1 instance per node) active/passive cluster is:1 Disk Quorum1 Disk MSDTC1 LUN UserDb Data1 LUN UserDb Logs1 LUN SystemDB Data/Logs1 LUN tempdb Data1 LUN tempdb Logs |
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dinakar
Master Smack Fu Yak Hacker
2507 Posts |
Posted - 2012-02-03 : 00:19:21
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| active/passive is incorrect terminology. Its either a Single instance cluster or a multi-instance cluster. An instance can be active on only one node at a time. A node can have one or more instances active on it.. Each instance has its own set of disks that are owned by the node the instance is active on. your list of LUNs are right though, for a single instance cluster. but "2-node (1 instance per node) active/passive cluster" is incorrect. There is only one instance and not per node.Dinakar Nethi************************Life is short. Enjoy it.************************http://weblogs.sqlteam.com/dinakar/ |
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Sachin.Nand
2937 Posts |
Posted - 2012-03-03 : 12:47:23
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| Any particular reason for selecting disk for MSDTC and Quorum ?After Monday and Tuesday even the calendar says W T F .... |
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deepaksahay09
Starting Member
3 Posts |
Posted - 2012-03-10 : 05:10:34
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| your comment is right. I think this knowledge is very help full to me ,because it is interesting news.unspammed |
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Recommended Cluster Disk Setup