SQL Server with Mr. Denny:

Storage


May 9, 2011  2:00 PM

EMC World 2011 Day 0



Posted by: Denny Cherry
EMC World, EMC World 2011

So today began EMC World 2011.  It started in true EMC style with a great party, sponsored by UniSys.  The party was held at the Hotel pool which seems a little strange but EMC made it work.  It was a little windy last night, apparently not even EMC can control the weather. I met some great...

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...


May 2, 2011  2:00 PM

Next week is EMC World, and I’m getting there a little differently than usual.



Posted by: Denny Cherry
EMC World, EMC World 2011

So this year EMC World is back in Las Vegas, and I'm damn happy that I'm going again.  Instead of taking the quick flight from Ontario to Las Vegas like I normally word, I'll be getting there a little differently, I'll be riding my motorcycle. As I can only...


April 28, 2011  2:00 PM

If i have 3Par SAN, is there any specific recommendations, as it does its custom stripping across the drives. or any other specifics related to 3PAR?



Posted by: Denny Cherry
Storage

The biggest recommendation that I have (pretty much the only one since I haven’t worked with a 3PAR in a while) is to ensure that your LUNs are sized correctly so that they are evenly spread out across all the disks in the disk set that you are using. For example, if you have 100 disks in the...


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


April 4, 2011  2:00 PM

Can tempdb data and log put on on RAID 1 one physical disk, or keep it separate physical disk?



Posted by: Denny Cherry
SQL Server, Storage, TempDB

It really depends on the amount of load that you put on the tempdb database.  Everything which is done within the tempdb database is going to be logged in the transaction log just like any other database so if the tempdb database has a very high IO then it may make sense to put the tempdb log on a...


March 25, 2011  2:00 PM

SQL Backup Compression and Backup Dedup are mortal enemies



Posted by: Denny Cherry
Backup & recovery, compression, SQL Server, SQL University, Storage

If you have a modern tape backup solution you probably have some sort of dedup process in your backup environment.  What these deduplication processes do normally is look at the data which is being written to the backup platform and remove duplicate values in order to save space on the tape backup...


March 24, 2011  2:00 PM

What is faster SAN or DAS (local disk), and most importantly why?



Posted by: Denny Cherry
Replication, SQL Server, Storage

So here's an answer to the great myth of SAN, it isn't always going to be faster than local disk (or DAS, JBOD, etc.).  The reason for this is actually pretty straight forward. Local disk is cheap.  That's the reason in a nut shell.  Let me see if I can't explain in a little more...


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