Please start any new threads on our new
site at https://forums.sqlteam.com. We've got lots of great SQL Server
experts to answer whatever question you can come up with.
| Author |
Topic |
|
MuadDBA
628 Posts |
 Posted - 2010-01-14 : 16:02:00
|
| Currently, my company tries to adhere to the conventional wisdom of keeping 20% free space on volumes both for performance reasons as well as for capacity planning. I am wondering how necessary this is for larger volumes. For example, right now I have a 1.6TB database that grows by 1 - 2GB per month. It is on a total of 4 drives, 2 809GB drives 1 400GB drive, and 1 146GB drive (logs). By maintaining this 20% free space threshhold, we've effectively tied up 320GB of very expensive Tier 1 Fiberchannel disk.I'm wondering if, once past a certain size, it's really necessary to maintain this level of free space. None of my DB files (and that's all that's on the disk) are large enough that I think we'd have to effectively move the whole thing to the volume free space to defrag it, and nothing is ever going to grow so quickly as to take up, say, 50 or 60GB overnight or even in a week without us noticing it (we have regular capacity reports and monitoring).So is this old line of thinking still valid, or is 10% or even less a better guideline once you reach a certain threshhold? any articles which support either conclusion? |
|
|
tkizer
Almighty SQL Goddess
38200 Posts |
Posted - 2010-01-14 : 18:24:23
|
| It's really a company's decision on what thresholds to use for each system. We use the 20%/10% thresholds here on most systems, and then on those that are quite large we use the 10/5% thresholds. The first threshold of either type fires an email when it is hit to the DBAs. When it hits the second threshold, the on-call DBA gets paged. It doesn't make sense to page a DBA when there is 320GB of free space on a drive and the database only grows 2GB per month, so we'd definitely be altering the thresholds here if that were my system.Tara KizerMicrosoft MVP for Windows Server System - SQL Serverhttp://weblogs.sqlteam.com/tarad/Subscribe to my blog"Let's begin with the premise that everything you've done up until this point is wrong." |
 |
|
|
|
|
|
|
|
Large volume free space requirements.