Hardware recommendation?

I am looking to build a better standalone SQL server. Current system is a Dell 2950 with six 7200 RPM SATA drives (slooooow) in a RAID 10 array. The OS lives on the same array as the SQL db. Also, current server has only 8 GB RAM and is running 32 bit Enterprise Server with AWE enabled.

Here are my options for a new server:

24 or 32 GB RAM, eight 15K rpm 146 GB 2.5" SAS drives. 6 would be RAID 10'd for the SQL db to live on, the other two would be RAID'd for the OS to live on.

24 or 32 GB RAM, six 15K rpm 450 GB 3.5" SAS drives. All 6 would be in the RAID 10 array but the OS would have to live on the same array as the SQL db.

Which is better? Old school was always better to have OS living on different drives. However, if I do that, I take a huge space hit, as I'd only have about 400 GB of space available for the SQL db. that should be plenty, but still...

Help? Is it important to have the OS not live in the same RAID array as the db?? I need to get this quote to my boss, ASAP.

TIA,

warbird

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Accepted answers

vhcato

Given a choice between the two options presented, I would have to go with #1. Keeping the OS separated on their own pair of disks (RAID 1), and the other 6 as a RAID 10 array for the DB should provide a significant improvement in performance given the obvious differences in the current and new hardware. Of course, that is if you are truly running into a disk IO bottleneck, and I assume you are.

As for the memory, more is deffinitely better. Also, make sure you invest in a good array controller.

All comments

qle

I don't know if you have an established standard or policy regarding the configuration of your servers but since you posed this question, it sounds like you have an option here. It's been my personal opinion to separate OS and data wherever possible. If you need to completely rebuild the OS for some reason, it's some comfort that this configuration will minimize any risk of corruption to the data.

It's a little ironic that you're worried about taking a hit on storage space while you'll be setting this up as RAID 10, though.

warbird

Thanks you. That is the direction I am tending toward. I do have some leeway to decide how the install goes. I am choosing RAID 10 because that is what the NPM docs recommend. It made a huge positive difference moving to RAID 10, even with the current slow 7200 RPM SATA drives we currently have.

The largest I have ever seen our Orions db's get to is ~75 GB (currently ~40 GB). I am hoping that 400 GB of disk space will be enough.

The other option I have is to move the db to SAN but that is recommended against.

ElisabethZakes

Warbird, remember Denny's post here on using a SAN. The major issues are configuration and write speed. But you can run Orion with a SAN. Also see here for use of AWE.

warbird

Thanks EZakes. We may not be able to use the SAN I mentioned in that thread and it may be desirable to keep the Orion SQL db on its own server. Hence these hard drive questions.

Reference the AWE solution, that has been working great. I am looking forward to moving to 64 bit Windows Server and 64 bit MSSQL so that AWE will no longer be a necessity.

vhcato

As for the memory, more is deffinitely better. Also, make sure you invest in a good array controller.

warbird

Thanks, vhcato. Yes, I was running into extreme I/O problems with the current disks, especially when they were in RAID 5. I was seeing average disk queue lengths between 400 - 800, just with NPM and NCM (NTA disabled). Changing over to RAID 10 got the avg disk queue length down to about 200. A couple of config changes in the NCM got it bouncing between 100 - 150. Enabling AWE (the SQL server is currently 32 bit) reduced the queue length to below 5! However, running NTA for any length of time introduces problems again.

I believe this new hardware for the SQL server should allow us to run NTA, although I do have a concern about how large the netflow portions of the db will get.

*edit* Forgot to include that because the server is a Dell, I am restricted to going with one of their PERC 6/E RAID controllers. I am going for the one with 512 MB cache.

vhcato

Yes, netflow data can definitely put a hurt'n on a disk array, as well as CPU's. Unfortunately, I'm not familiar with with the requirements of NTA, as we use a different product for our netflow needs, but depending on your data retention requirements, flow rates, and the number of interfaces/devices from which you're receiving flow data, this could require substantial server resources to store the info and present it in a timely manner.

DirtySouth

SQL servers in general would benefit from data in a raid 10 and OS in a raid 1. Were using a 2950 for our SQL server as well with 4 drives in a raid 10 and two in a raid 1. Performance seems fine.