Short for 'Storage Area Network', a SAN is a network for block level storage. One or more controllers present logical drives (called LUNs) to one or more hosts through a switched fabric.

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I/O requests taking longer than 15 seconds

Usually our weekly full backups finish in about 35 minutes, with daily diff backups finishing in ~5 minutes. Since tuesday the dailies have taken almost 4 hours to complete, way more than should be ...
13
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3answers
2k views

Is there any benefit to defragmenting SQL indexes in a SAN environment?

Our SQL server lives on a SAN. It contains dozens of OLTP databases, some with several tables containing over 1m records. We have been running Ola Hallengren's index maintenance scripts weekly, and ...
8
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2answers
2k views

SQL Disk Setup Advice - TempDB, Log DB, Data file placement question

We have a very active database server with a ecclectic collection of applications running on it. Two of the busiest are a Laserfiche database that does document scanning and workflow processing all ...
5
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3answers
10k views

T-SQL query to report disk space allocation and used space for auto-grow SAN databases

We are using 6 databases in total for an application, and we can only share 4TB of space for all 6 databases (via SAN storage). I'd like to write a query (report) for a single database indicating the ...
5
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4answers
4k views

SQL Server - Separating data, log, and TempDB files on a SAN

I have a SQL Server connected to a SAN. Our new storage vendor recommends that all LUNs span the entire disk array, which is RAID5. I would normally request 3 separate LUNs (data, log, and TempDB) ...
4
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2answers
5k views

SAN block size for SQL Server on 4KB NTFS

A potential customer wants to evaluate our storage system. They run Windows 2008R2 x64 with 4KB NTFS on a virtual test machine they've sent us. They did not seem to know this at hand, so I think it's ...
3
votes
3answers
432 views

Database IO comparison

We're running sql server on vmware. Our san is pretty new but still I think I/O is pretty crappy even though I'm supposed to be on separate spindels. Server speeds are: My client machine: Is our ...
3
votes
1answer
88 views

Storing Tlogs and data files on the same drive

I'm looking for some clarification of various things I've read. I understand it to be best practice to store your transaction logs on a separate drive (spindle) than where you MDFs and NDFs are ...
3
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2answers
1k views

Multiple SQL Server data files on same SAN disk

I'm currently in the process of creating a new database, and have previously only ever used a single data file and a single log file. I've done some research online regarding the benefits of multiple ...
3
votes
1answer
77 views

Should I align my SQL Server file and growth sizes with the block sizes on my SAN?

It was brought to my attention that our (Hitachi) SAN handles data in 42MB blocks. It is tiered storage so each block is evaluated when the director makes decisions as to when it should promote/demote ...
2
votes
1answer
92 views

Sql Server & NetApp Sql Snap Manager

Does anyone use netapp's sql snapmanager? We are in the process of trying to decide if it is right for us. I know of the more popular features, but am trying to get some real life experience ...
2
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2answers
409 views

Investigating/Troubleshooting I/O Spikes

We have been experiencing some relatively large I/O (IOPS) spikes on the SAN that supports our production SQL Server. The spikes seem to fall at an exact time after the hour, each hour. We have ...
1
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2answers
264 views

Understanding disk requirement to make fail over cluster

Please take a look at the following screenshot. I am trying to make SQL Server 2012 Fail Over Cluster using two nodes. As you know we need to have a shared SAN which will be used by both nodes to ...
1
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1answer
120 views

Why does innodb_flush_method = O_DSYNC provide such a performance boost with SAN-backed storage?

I've seen some people suggest that O_DSYNC should be used with a SAN. The MySQL docs have this to say about O_DSYNC in general: In some versions of GNU/Linux and Unix, flushing files to disk with ...
0
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0answers
30 views

VM SQL Data and Log drives have one Block Size, SAN another. Issues?

Setting up a new SQL VM. What happens if VM data and log drives have 64K (recommended) block size but SAN (IBM DS3500 Express) was configured with a different block size? I want to avoid IO issues ...
0
votes
1answer
44 views

Slow SQL Server authentication, but fast SAN, fast querying?

I am asking you after days of research but I think I don't have required skills to understand what is happening. I have a slow authentication on a SQL Server 2008R2, which leads to a timeout for the ...