October 5, 2007 at 1:25 pm
Hello,
I have RAID 5 and total size 1000 GB.?
I created 3 partitions :
C drive (O/S only)
E drive (SQL Server 2005 only)
F drive (Log only)
Can anyone recommand C drive partitoin prefences for the O/S.?
Please help and advise. Thank you.
TJ
October 5, 2007 at 2:02 pm
Correction: Can anyone recomand the HD size for O/S.?
October 5, 2007 at 3:35 pm
I guess it depends. Do you have any other apps planned to be installed on the OS partition? do you have multiple instances going to the box? are you going to move the system databases off the OS drive? (temp db can grow to be large in some situations. How much RAM (this can affect the page file). All that aside, I usually give about 30 GB to my os so it has some room in case something come up where we need to install other apps, tempdb growth, pagefile, etc.
October 8, 2007 at 9:12 am
hi Old Hand,
Thank you for your inputs.
+++ No, I did not plan to install any apps on O/S drive.
+++ I did not plan to install multiple database instance.
+++ Yes, I am planning to system databse off the O/S drive
+++ 2 GB RAM Memory
What is the recommanded RAM for RAID 1 + 0 (RAID 10).?
Thank you.
TJ
October 8, 2007 at 9:18 am
TJ,
Old Hand is a rating based on posts, not the name. The name is above that in bold, so it's Adam you were responding to.
Second, RAM isn't related to RAID. Are you the admin for the server or a developer? The reason I ask, and it's not to insult you, but it sounds like you're lacking experience from the server side.
It's hard to recommend since you haven't given any DB or log sizes or any other needs. It would be better to go larger on the OS if needed, especially if you might need a large pagefile. With 2 GB RAM, then 30GB should be fine for the OS partition and give you space to grow.
Also, how many drives make up the 1000GB?
October 8, 2007 at 12:47 pm
Hi Adam, & SSChampion,
Apologies!!!! I just relized my typos. It should be addressed to Adam 🙂
I am not the admin of the server but I can survive use the window server 2003 O/S. 🙂
It is not a rocket and science.
The largers DB 100 GB ++.
October 8, 2007 at 9:23 pm
I usually go with a 20-30GB O/S partition when in a situation like yours. I prefer either 2 32GB or 2 72GB drives mirrored in hardware but that's just me - the day we need 72 GB for an O/S? Ouch.
I have seen Windows 2003 installs with all patches, etc. consume > 20GB though.
October 10, 2007 at 8:12 am
I would go with at LEAST 30GB for OS partition - perhaps 40. Seems like EVERYTHING these days puts crap in the os part - especially the installer directory. My new laptop isn't fully configured yet and I have 3+GB just in that folder. .NET crap, patch crap, swap file, etc, etc. Heck, even sql 2005 when specified to 'install' on a different partition puts almost half a gig in program files...
BTW, RAID 5 is NOT a good choice for all of your stuff. Actually it is a POOR choice for most of it.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
October 10, 2007 at 5:10 pm
TheSQLGuru (10/10/2007)
I would go with at LEAST 30GB for OS partition - perhaps 40. Seems like EVERYTHING these days puts crap in the os part - especially the installer directory. My new laptop isn't fully configured yet and I have 3+GB just in that folder. .NET crap, patch crap, swap file, etc, etc. Heck, even sql 2005 when specified to 'install' on a different partition puts almost half a gig in program files...BTW, RAID 5 is NOT a good choice for all of your stuff. Actually it is a POOR choice for most of it.
As TheSQLGuru mentions, RAID 5 is not necessarily the best choice for everything. You've got the right idea with splitting things up for OS/SQL data/SQL logs to begin with. If your db will experience modest use, then you could be fine with this configuration. If the db is heavily used, though, you may run into the limitations of this setup.
Things to consider in that light:
- although you've got things split up into 3 partitions, those partitions exist on the same physical disks. If all three partitions are heavily used, you can still wind up with an i/o bottleneck as the heads thrash about, trying to keep up with the activity.
- ultimately, RAID 5 is more suited for reading data than writing, as there is overhead with every write (update/insert/delete/etc) for parity calculation. If the db writes often and is in full recovery mode, you're more likely to hit this wall. (keep in mind, too, that access to the db data will be random, whereas the transaction log drive access will be more or less sequential)
- under load, perfmon counters for disk usage can quickly tell if disk i/o is an issue -- watch your partitions for high utilization (you may even see them hit 100% usage for seconds at a time under heavy load -- definitely not optimal performance)
- depending on how many drive bays you have available, and what RAID levels your controller will support, you may consider having the SQL data and log files on their own separate arrays
- one app I work with really gives the db server a workout, and so we've got the OS on a 2 drive RAID 1 with 10K RPM drives (simply for redundancy, since it's low usage), the SQL data on a RAID 10 with 15K RPM drives to deal with heavy read/write activity, and the transaction logs on yet a third array (preferable RAID types will depend on your situtation) (In this fashion, I've seen a 4 drive RAID 10 outperform a 7 drive RAID 5, all else being equal)
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