SQL Server with Mr. Denny:

SQL Server


May 23, 2011  2:00 PM

On an EMC array is it possible to assign WRITE cache to wherever your transaction log files are?



Posted by: Denny Cherry
EMC, SQL Server, Storage

Yes, provided that your transaction logs have their own LUN from the other files as the write cache is enabled and disabled at the LUN level.  By default read and write cache will be enabled for every LUN which is created on the array. There aren’t to many cases where you would want to...

May 19, 2011  11:00 AM

Should a VMs virtual disks all be on the same storage?



Posted by: Denny Cherry
SQL Server, Storage, Virtualization

A question that comes up when building a new virtual SQL Server is how should the disks be laid out when using the default VMDK (VMware) or vDisks (Hyper-V)?  Should the disks be on a single LUN, or different LUNs, etc. I’m sure that it will surprise no one when I say that it depends.  On a...


May 16, 2011  2:00 PM

Getting rid of those annoying backup successful messages



Posted by: Denny Cherry
SQL Server, SQL Server 2000, SQL Server 2005, SQL Server 2008, SQL Server 2008 R2

If you have a SQL Server, and you are doing transaction log backups on the database server you’ll notice that 99% of the messages in your ERRORLOG file are worthless.  All they say is that the log was backed up successfully.  Personally I don’t care that every 15 minutes all 30 databases had...


May 13, 2011  7:54 PM

Let your opinion be heard for SQL PASS.



Posted by: Denny Cherry
SQL PASS, SQL PASS 2011, SQL Server, Stacia Misner

I'm a couple days late getting this post out, thanks to being at EMC World, but here it is. This year the PASS Summit is asking for your help in deciding what sessions should be presented at the SQL PASS summit in Seattle later this year.  To do this they have created the


May 11, 2011  4:16 PM

EMC World Day 2 (2011)



Posted by: Denny Cherry
EMC World, EMC World 2011, GreenPlum, SQL Server, VMware, VNX, VNXe

Yesterday was EMC World day 2 and it was another great day at the conference. I started the day a little late as I was out pretty late on Monday night at a party. I was abe to great some great sessions in during the day however. The first session that I hit was "SQL Server on VMware -...


May 10, 2011  2:00 PM

EMC World 2011 Day 1



Posted by: Denny Cherry
EMC World, EMC World 2011, SQL Server

So today was the first official day of EMC world. I had a great time meeting some fantastic people like Chuck Hollis from EMC. There were also some fantastic sessions. This year EMC is doing something new and putting the sessions online through an iPad app as well as putting them on their...


May 5, 2011  2:00 PM

Enterprise environment are moving more and more towards service oriented functional groups. SAN as a service, database as a service, etc. So SAN guys are saying DBAs shouldn’t worry about this, they use gigantic arrays with 100′s of spindles, they guarantee performance, etc. What are your thoughts on this?



Posted by: Denny Cherry
SQL Server, Storage

I would say that the SAN admins are nuts if they think that the DBAs aren’t going to worry about storage performance.  There is no magic SAN dust which keeps everything running fast all of the time.  If you put enough load on the array then performance will be impacted, no matter how many disks...


April 25, 2011  2:00 PM

We get many warnings in our SQL error log about I/O requests taking longer than 15 seconds to complete. What do we do in such scenario?



Posted by: Denny Cherry
Index, Index Scan, Index Seek, SQL Server, Storage

There are a few things which you will want to look at.  First make sure that you have enough RAM for the database to use.  Without enough RAM in the SQL Server you’ll begin putting extra load on the disks because the same data is being pulled into the buffer cache from the disk over and...


April 21, 2011  11:00 AM

Is there a best practice to advise a storage admin how to set a SAN up best for SQL Server OLTP & OLAP? or is this entirely company dependent?



Posted by: Denny Cherry
SQL Server, Storage

There are some general best practices such as separate data and log LUNs, separate TempDB from everything else.  For data warehouses make sure that the data is spread over as many disks as possible.  Anything more specific however is very company specific and would require a good understanding of...


April 18, 2011  2:00 PM

For SQL, best practice is to have data on one array, logs on another array and tempdb on another array. how does this work in san world? SAN people don’t really give all these options when assigning storage for database server.



Posted by: Denny Cherry
EMC, SQL Server, Storage

Even when using a storage array it is typically best practice to have the data on one LUN, logs on another LUN, and tempdb on another LUN.  Especially if you have the option to putting each LUN on different physical disks.  If you I talked a little more about this a


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