SQL Server hardware configuration

davmac1 · 2008-05-19

Our local Microsoft Navision SE (this is a Microsoft employee in the local sales office) is recommending RAID 10 for the log file. This is counter to every recommendation I have seen of using RAID1. He says RAID 10 is always better than RAID1.
Since the log file is written sequentially, would RAID 10 actually help (and not hurt) in a high volume situation?
He is also recommending splitting the drive pairs between each channel of a dual channel SCSI RAID controller. I have never heard of doing that before, and when I asked the Dell support engineer, he said he would have to get back to me, after he consulted an internal expert.
(In other words, you would put a single set of RAID 10 drives on both SCSI ports and treast them as one logical drive.)

Has anyone have any feedback on this?

garak · 2008-05-19

Take a look here: http://www.mibuso.com/forum/viewtopic.p ... light=raid

Regards

Waldo · 2008-05-19

Or here

Or the download.

garak · 2008-05-19

fileformat pptx #-o
why not pdf :?:

Waldo · 2008-05-19

Mainly because I'm lazy :oops:

garak · 2008-05-19

tzzzzzzz

davmac1 · 2008-05-19

Thanks - I have never seen anyone else propose RAID 10 for the log file - on this forum or Convergence.

How about the dual channnel SCSI looking like a single logical drive?
My research so far does not show any support for that idea - that each channel is trreated like a separate SCSI device. Any hardware specialists in this forum?

DenSter · 2008-05-19

If you have more than 2 drives, RAID1 won't cut it, so the logical choice for 4 or more would be RAID10 (unless you split up the log file across multiple drives). I don't know if you can say "RAID10 is always better than RAID1 though, that seems like too much of a generalization.

Waldo · 2008-05-19

I don't know if you can say "RAID10 is always better than RAID1 though, that seems like too much of a generalization.

Why?
Seems very obvious for me...
:-k

DenSter · 2008-05-19

Well for starters, what does 'better' mean? Better for the environment? Better for performance? Better for budget reasons? Better for what?

Then it depends on the situation whether RAID1 or RAID10 is more suitable. If you have a limited number of spindles at your disposals you might want to choose more disks for the data files, or maybe there are other reasons.

My point is that you first need to analyze the situation before making a statement about what is 'always better'.

Waldo · 2008-05-19

For me it means "better performance", off course. I never look at the budget

.

David_Singleton · 2008-05-19

Seriously without knowing your system NO ONE not any expert can make hardware recommendations. If you have decided on a $1,000,000 budget for the server, then YES RAID 10 is better. But if (like 99.99999%) of companies in the world, the client is working to some budget, then its necessary to look at every aspect of the system, and balance it out. For example if they have a RAID1 with 2 drives, and a RAID 10 with 8 drives, then you would put the DB on the RAID 10 and the LOG on the RAID1. So in this case clearly RAID1 is FAR worse for the log file.

Also how much RAM do they have? What TempDB do they have? How many CPUs? Imagine that you had to choose between 4 drives in RAID10 Log file and 2 Gig ram, or 2 Drives in RAID1 Log and 16 Gig of RAM. Which is better?

Please let us know the full story, because ANY expert that gives expert advise without knowing your needs, is not an expert.

Also, in my very humble opinion, the single best value for money investment you can make in your SQL server, is getting a NAV SQL performance expert to come in and tune the database. That money will ALWAYS give you the best ROI. And there are a ton of them on this forum that can help.

(Sorry about this post :oops: I know its a little bit angry, but please people, every system is different, and what works for one system may not apply to any other.)

David_Singleton · 2008-05-19

Davmac1,

I think whats happened, is that someone at MS read something somewhere, and used it out of context. There is a chance that this suggestion MIGHT help your situation, and pretty certainly it wont cause any harm, BUT I doubt that they really looked at the total cost of implementing this, and balancing that against the many other things they could do.

The danger now is that if you don't follow that persons suggestion, and ANYTHING goes wrong, they can come back and say "See I told you so, you should have listened". Even if the issue has no connection what so ever to the problem. You unfortunately are sitting between a rock and a hard place right now.

davmac1 · 2008-05-20

What is interesting about all the posts is noone picked up on the hardware portion - according to Dell, you cannot implement a single hardware RAID volume on two ports.

garak · 2008-05-20

For people how will know: "What to hell is RAID" Here a link:

http://en.wikipedia.org/wiki/RAID

David_Singleton · 2008-05-20

davmac1 wrote:

What is interesting about all the posts is noone picked up on the hardware portion - according to Dell, you cannot implement a single hardware RAID volume on two ports.

I am pretty sure that most of us have delt with IBM, HP nad Dell. My gernearl experinece with them when asking for a complex Hardware configuration is:

IBM "You just let us work out the hardware...that's our job"
HP "You want what?... hmmm now that sounds expensive..."
Dell "Say what? No way ... that's impossible"

My experience with Dell is that you need to talk to three or four reps before you find one that can give you the correct answer. Of course it may well be impossible, but you do need to ask a lot of people before you can be sure.

Oh by the way, I have a client with a rather large database, because of the way their NSC advised them, they have their LOG file split over 8 drive arrays. & of the arrays are for decoration, and one of them does all the work. In the mean time they have another 8 arrays for the DB that area all at 100% capacity. In their case, the better configuration would have been 15 arrays for the DB, and one for the LOG file. This is one example why more drives for the LOG file is not faster.

vanrofi · 2008-08-29

Wall-do,

Your download only gives me a tree of folders with nothing but XML files and jpegs in it...can't open it in PPT...is something wrong with the download or with me? (only refer to the download when answering pls :-)

Waldo · 2008-08-29

Hm, that's strange... .

I got the same problem. Actually, it's a pptx file, but it's downloaded as a .zip.

renaming the file from .zip to .pptx does the trick.

What's the cause? I don't know ...

vanrofi · 2008-08-29

Next time we see each other, I will NOT forget to kiss you for this! :^o

Many thx!

We have an HP DL 580 R 2003, 64 bit with 2 quadcore 2 and 4 ghz, 16 gb Mem, 2 SCSI controllers, 1 for OS and Log, and for DB, both in Raid 1+0...so Hardware-wise this swalloped some budget but should cope with the load, now investigating the SQL-setup...probably need some SQLtuning once we are Live...Mibuso.com, here I come...

Waldo · 2008-08-29

I thought you would say ... iFacto, here I come

vanrofi · 2008-08-29

never say never again.
Problem is that Love and Business is a dangerous cocktail :-s

David_Singleton · 2008-08-29

Waldo wrote:

I thought you would say ... iFacto, here I come

vanrofi wrote:

never say never again.
Problem is that Love and Business is a dangerous cocktail :-s

Too much information guys

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