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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ms/write on tempdb data files are dead slow

I don't know why writes on my tempdb data files are extremely slow. ms/write on each of the tempdb data files reaches to more than 800 ms!!! that's even after I moved the 8 equally sized (7GB) tempdb ...
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30 views

Is it possible to query the avg time in ms per read/write

I was wondering if it was possible to obtain the avg block read and avg block write in ms with a query in SQL Server. If SQL Server knows how many IO requests are made for a given wait type and how ...
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17 views

What is faster Asynchronous SAN Replication or Asynchronous AAG?

If copying data from one datacenter to another, what would generally be the faster approach to propagate that data to the target datacenter, SAN Replication or AAG, i.e. block-level or transaction-...
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1answer
198 views

SQL Server on SAN, same LUN: one logical drive vs multiple

First, let me start by saying that I did notice there are multiple similar questions to this, but neither of them is exactly what I want to ask, and not one of them has a definite answer. Second, let ...
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2answers
66 views

SAN for SQL Server: One large spindle set for all loads, or discrete by load?

SQL Server 2014, Standard Edition (running under vmware, fwiw). Adding a Dell MD3420 DAS box. In the old school, you would set up discrete spindle sets for MDF, LDF, TEMPDB, BACKUP. E.g. MDF: Qty ...
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49 views

If my Data, Log and Tempdb drives are on the same LUN, are they using 1 physical drive?

My SQL Server Data, Log and TempDB resides on different logical drives. But when I check the drive properties under Hardware tab, their location are located on the same Port, Bus, Target ID and LUN. ...
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1answer
81 views

SMB 3.0 file share storage limitation

What is/are the limitation/s to move from SAN storage to SMB 3.0 on windows Server 2012 - SQL server 2012 enterprise production environment? I want to know the benefit of using SAN over SMB 3.0 as ...
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2answers
66 views

A new SAN - good idea for us? [closed]

I work for a small non-profit organization which has 2 infrastructure administrators. They have experience with Windows server administration and virtualization, but no experience with SANs or SQL ...
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31 views

Correlating Disk Latency on Application side Vs. EMC SAN

Our OLTP databases have encountered several I/O issues. During those events: Avg disk sec read on the data file was 0.2 second or higher We found windows eventlog entries stating: "SQL Server has ...
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1answer
51 views

Migrating system and user databases to a new server by moving the lun

I have to lease replace a server and the system and user databases all reside on the e which is a SAN LUN. The method they want to employ is to remove the lun from the current server and present it to ...
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66 views

What is the ideal disk allocation size using our Nimble SAN?

I have seen many recommendations to use 64K disk allocation size for data drives such as from the SQL Server Setup Checklist on BrentOzar.com. The best practice guide for using our Nimble SAN with ...
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1answer
172 views

Why is SAN Replication is Causing Random Database Corruption?

Having a strange issue with a disaster recovery technology we're trying to implement. The environment in both datacenters is the same having VMWare and Dell Equallogic SANs, which are the same ...
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1answer
65 views

SQL Server : multiple databases with transaction log on one SSD array

I know for HDD arrays that having multiple log files from different databases has a performance hit as it changes the IO pattern from sequential to random for the array. So having an array per ...
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1answer
397 views

SQL Server Database File Groups on a SAN: Relevant or Not?

I am about to build out a new SQL Server and I was planning to make extensive use of file groups. I expect heavy growth, and heavy read/write to 5 different databases on this server. I was planning on ...
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66 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 ...
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3answers
513 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 ...
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2answers
1k 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 ...
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1answer
124 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 ...
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1answer
131 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 ...
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2answers
529 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 ...
3
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1answer
107 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 stories....
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2answers
2k 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 ...
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4answers
8k 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) ...
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2answers
13k 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 ...
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3answers
967 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 ...
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2answers
685 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 ...
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3answers
3k 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 ...
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2answers
10k views

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 ...
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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 ...