Adaptec 5805 and 8 SAS 15k.5 query...

phill9800

phill9800

phill9800

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Hi guys,

I've recently been testing a few hard drives with a few different controllers. I recently started playing with SAS drives and when I found 6 73Gb 15k ones I jumped at all 6 and found they where amazing...
Then I found 8 Seagate Cheetah 15k.5 drives which completely blew me away with its speed and response times.
But when I added my 6th 15k.5 I noticed the scaling wasnt there like it was from drives 1 to 5.. I tried 7 and then 8 and got very little increase.
I've tried all the ways I can think of (limited maybe) of how to try and speed this up (different stripe sizes, format sizes, how I raid the drives, what ports they connect to etc etc) but nothing seems to make a blind bit of difference...

Please oh please could someone advise me what to do, since I really have no more idea's left and the thought that a 1000mb/sec performance is there and I just cant quite get it, is frustrating me!! :lol:

Any help would be great.. Oh my current rig is:

E8600 @ 4.5Ghz
2Gb DDR2 ram @ 1080Mhz
S3 Virge 4Mb PCI card (so the adaptec has the full 8x PCIe it needs)
Hitachi 250Gb - just for OS
8 x Seagate Cheetah 15k.5 73Gb drives
Adaptec 5805 controller (latest firmware) with Adaptec SAS cables
Silverstone 1000w PSU fully modular
30" Dell 3008 WFP screen

If you need anything else, please shout :) Thanks for reading and help in advance!! If you'd like screen shots of tests I've completed, please just ask :)
 
As well as the controller, it's OS and application dependant once you get large numbers of drives. What do you need the speed for? Have you seen and increase in IOs with more drives?
 
I'm wanting this for a gaming rig and thats it really :D There's been a lovely increase in performance with going from 1 drive to 5 but thats where the performance seems to really stop getting any higher and making much of a difference, which I must admit, I'm a little gutted with :(
 
Hi Phill

How are you testing the scalling? I assume you are benchmarking? You may find you have reached the fastest speed the roc procs can go. I know HDDs don't scale linearly but would have thought you would have seen an increase in sequential reads as long as the read test is reading a file longer than your stripe * drives. I would conclude it is either the benchmark not allowing you to see the speed increase or your system has hit a bottleneck probably in the raid procs.
 
I basically started off with one drive, then added one more, tested, added another, tested, added one more etc until i had 8 installed in the system..

What worries me is the raid processor on the card is a dual core 1.2Ghz (or 2.4Ghz I forget which) with 512mb of ram.. I'm surprised to be honest, it cant manage more...

I used all sorts of different tests, from HD Tach to HD Tune, Crystaldiskmark, ATTO and a few others.. I even tried PC Mark 05 with it as well. I have saved every test I did with a screen shot :)
 
I'll probably get shot down, but I could swear I read somewhere that as a rough rule of thumb the processor speed on the controller is the 'speed' limit for the card (ie. 1.2Ghz with give you a max throughput of 1.2GB/s) - I'll dig about, but I'm sure it was one of those mad review sites that tested a silly number of SSD's when they 1st started appearing in the mainstream, and he kept hitting the controller limit.

Remember also the pure read/write speed is only a tiny piece of the story - especially with these kinds of drives - it's all about the IO performance in a server environment (not much use in gaming) - where you are winning is on access time - I found that made the biggest difference when I had my old Scsi Cheetahs. Worth checking to see if your card supports the Raid 1 mode that splits searches across drives giving you quicker access times - would be of more use than all out speed ;) (perhaps some sort of a Raid 10 would give you the best of both worlds if it did support whatever the split read function is called?)
 
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Well this is what I was thinking as well, but its sadly not the case in my current setup.. I did wonder if it was down to the motherboard I was using... Maybe I could re-try with my i7 setup when I get it?
 
you have hit the limit of the raid controller.

The raid controller is PCIe x8 but you probably have it in a pci 2.0 slot which is double bandwidth anyway so slot bandwidth is not the issue.

The issue is the ROC it is going flat out.

Your only option is to get a second card and set the volume across both cards I think this is possible if not with Adaptec with RAIDCORE.

Fire off an e-mail to Adaptec they will be able to give you some advice. 1.2Gig is the theoretical limit on your card.

If you haven't already you could try changing the controller to OLTP mode which might give you an increase in performance on some benchmarks.
 
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Well thats a rightous pain in the arse... There's no way I'm gonna go spending another £400+ on one of these cards!! :lol:

Just wondering how they managed to get a faster result over at Anandtech with 8 of the 300Gb Seagate models... I dont know how to go about doing it..

I would have thought there was surely more room with this card.. Hell, its meant to handle 256 drives and its falling down with 5!! :( Something surely isnt right there...
 
did you Try OLTP mode?

You can't get past an absolute limit of 1.2ghz of the ROC.

You are happy to keep buying the drives which are not that cheap but you don't want to buy another controller?

I assume you are running RAID 0 across all 8 drives? I take it you are not worried about drive failure then?

You are setting this up for a gaming system but to be honest mate sheer throughput and in this case IOP's that will be off the scale is overkill.

You have probably long hit the point where you are not noticing any difference except in benchmarks.

My advice and this is just advice is to consider SSD drives. Their write speeds will not compare to your SAS drives but the reads and IOP's will be higher. They are silent and you would probably only need 3-4 drives to max out your controller ;-) Their access times however leave any spinning drive in their dust and access time will make a difference for you if you have to have the ULTIMATE gaming system.

Don't get me wrong the SAS drives you went for are the best drives you can buy and leave an SATA drive in the rear view mirror but SSD's are better still.
 
I dont recall seeing a OLTP mode to be honest, so I'll have to say no I havent tried that...

Well these drives retail at what, £150 each? I paid half that for all of them as I seriously wouldnt have bought 8!!
But I think I already said why I went SAS rather than SSD, but I'll mention it again, just incase I hadnt..

I basically went for these drives over SSD's because of the price, capacity and performance. I dont believe that the SSD's are at a point just yet where I'd buy them mainly due to the size for the cost and I dont like the speed of them. Some of the write speeds I see are all over the place and I'm unsure if thats the software using to bench or not, but until they are lower in price and as big as these SAS drives, I aint moving.

Besides, the reason I tested all 8 at once, was to see whether or not there'd be any problems and since they is, I'm contacting Adaptec to see what they have to say about it and to see what they suggest.

I know SSD's are better, but I dont think its still right to buy them, what with the slow down after they have been used a bit and the fact they are still fairly new tech for mainstream home users.

I was tempted with 8 of the SSD's (OC Z Vertex if I recall) but the price/size just put me off since I've had a play with these SAS drives, they really are something out of this world.
 
Bear in mind that the controller isn't really aimed at a gaming style system.

What are you running it under. I dare say that if you placed the system as a storage system something like OpenFiler for a VMWare system that would likely continue to see it increase in performance with more spindles.

XP/Vista is probably the limit here.
 
Well again the controller was such a bargain I couldnt really say no to that either and I figured since it was one of the top of the range Adaptec SAS/SATA cards they did, I figured it would be the best thing to go for, because one thing I hate is spending money twice on things!!

I'm using XP 64 with these drives (or I will do when I get the system rebuilt since I'm upgrading to i7) I've decided to just stick with 4 drives in raid 0 and another 4 in raid 0 and I'll have lightening drive access and very nice drive copying speeds.

I did run the HD Tach quick/long tests side by side (so 4 drives and 4 drives) and what resulted was 450mb/sec plus on each array when they where used at the same time, so I was a little confused as to why it wouldnt work the same with 8 drives plugged in.. Strange..
 
Here is where you will find OLTP setting.


adaptec.jpg
 
Phil if you are chasing benchmark numbers and having fun then np. Enjoy....wish I had money to spend in that fashion. Hope you crack the magical GB/sec.

However you say its being done mostly for games.... Its not gonna affect fps. It will load games quicker but IMHO going above 1 Vertex is going to make only minor differences that most people wont even notice and even then if you are playing online in many games you will be watching a timer count down so all the other slow pokes have time to load the game as well.

But to help you in your quest. If you want a super responsive system follow the OCZ guides for the SSD's. The tuning they do will improve performance on any system not just one running on SSD's. Some more risky than others but if you running RAID 0 then data loss is obviously not high on your list of concerns.

Things like turning off modify and access timestamps, NTFS journaling, NTFS memory usage, ect ect. Many small things that all add up.
 
Well I've stopped 'chasing' numbers since I think I've tried most of the things that I thought would have made some difference to how the drives would/should have performed.

I know its not going to effect how fast the game runs, but I know at least that my games will load and be as fast as possible with this setup.

When I get my new rig through and setup properly, then I will have a look into seeing if I can make things go faster. I'm also trying to get an email over to Adaptec to see if they have anything to suggest or try since I've not really had much experience in the Raid field.

Since running Raid 0 there wont be anything on there thats important to me in anyway shape nor form. Everything will be kept on my Server which will have all of my data stored on different drives so that things wont go missing or so that I will loose data.

I hope I have thought of everything, but I'm sure there's something that'll bite me on the ass I'm sure!! :lol:

Thanks for the advice :) When I have the 8 15k.5's connected up again, I'll see what I can do :)
 
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