Planning performance RAID array

[congo]

I want to order some gear today, just after your thoughts.

I want to set up a RAID 0 or RAID 0 + 1 array and I was going to use 2 x 200gb Seagate NCQ SATA drives but they have risen in price due to popularity I guess. I was looking at the Western Digital SATAII 200gb drives which end up $40 cheaper for me.

Also, I spotted a special on today for Samsung SpinPoint 200GB 7200RPM 8Mb drives for $110, (I'm guessing they are ATA) this would save me $80 over the Seagates.

I've read that in real useage, there isn't much between all the drives in performance (with the exception of WD Raptors and the like), So, do you think it's worth trying to penny pinch here or not?

The RAID 0 array offers me double the I/O speed of a single drive. Will 2 x 200gb drives be as fast as 2 x 80gb drives?

I have a these drives now, 80gb, 120gb, 160gb (Seagates), and I know how the size thing works with RAID, in other words, if I mix hard disks in the array, I get the size of the smallest disk. My plan was to RAID 2x new 200gb drives and use the 160gb in another machine and use the 80gb +120gb as manual backup for my RAID array.

Can anyone see a better way or advise on the drives?

[NicksFXHouse]

I want to order some gear today, just after your thoughts.

I want to set up a RAID 0 or RAID 0 + 1 array and I was going to use 2 x 200gb Seagate NCQ SATA drives but they have risen in price due to popularity I guess. I was looking at the Western Digital SATAII 200gb drives which end up $40 cheaper for me.

Also, I spotted a special on today for Samsung SpinPoint 200GB 7200RPM 8Mb drives for $110, (I'm guessing they are ATA) this would save me $80 over the Seagates.

I've read that in real useage, there isn't much between all the drives in performance (with the exception of WD Raptors and the like), So, do you think it's worth trying to penny pinch here or not?

The RAID 0 array offers me double the I/O speed of a single drive. Will 2 x 200gb drives be as fast as 2 x 80gb drives?

I have a these drives now, 80gb, 120gb, 160gb (Seagates), and I know how the size thing works with RAID, in other words, if I mix hard disks in the array, I get the size of the smallest disk. My plan was to RAID 2x new 200gb drives and use the 160gb in another machine and use the 80gb +120gb as manual backup for my RAID array.

Can anyone see a better way or advise on the drives?

Put the two drives together that have the best (and matched) access times, rpm and largest cache. Don

[Mick_C]

I want to order some gear today, just after your thoughts.

Nick N posted just as I was, so I won't repeat the excellent advice he gave you...

Hey congo. Did you get those teeth whitened lately? lol! When I had my business running I bundled only Western Digital equipment on every unit I built for a reason.  Warranty issues can cost more than they're worth to a mom and pop business like I had. I've done loads of failure analysis and recovery on many brands, and rarely do I see Western Dig..  but this is not an absolute! (enough sales talk)

[congo]

Thanks guys!

I was going to set this up before Christmas, but they screwed my order up so I got the trots and cancelled it. They also put the prices up since.......... GRRR

I think I'll get this one, I've been using this brand for years and they have been good to me, not only that, but this one has an 8ms seek, and the WD is 8.9ms

http://www.seagate.com/support/disc/spe ... 826as.html

Thing is, my supplier lists 2 model numbers next to the item, and this means "whatever we have in stock".

The other model number they show is the older 8.5ms drive, still faster than the WD but it is the same expensive price as the new 8ms drive.

I spent all day again messing about on this, I'm my own worst enemy. Still never got around to ordering the drives, I won't do it until tomorrow now, they are closed

[Joe_D]

OK, I have been running RAID 0 in my gaming sys for a couple of years now with 2 WD raptors and there have been absolutly no problems.

I fact I like this setup so much I got two more Raptors for my all new sys I put together recently.

A RAID 0 array is treated just like a single disk and can be partitioned, etc as you wish.

A RAID 0 array wil not be twice as fast as a singe disk or any where near that. However, it wiil give a bit faster performance, enough to make it worth while.

A word on chunk/strip size: You will be asked to choose one when setting up

[congo]

I just installed the 2 new WD 200gb SATA II drives, I started configuring my bios for a raid setup, then thought, "hey, I'll just go into windows for the hack of it to see if the drives are there"

Well, they weren't , so I went to disk management and saw them in there as blank disks, and a requestor popped up asking me if I wanted to do a striped RAID volume!

I set 3 of these up immediately following a couple of prompts for chunk size and size of the partitions.

I set 20gb for the first, 100gb for the second and 70gb for the third partition.

I just ran SiSoftSandra HDD benchmark on the first 20gb RAID partition and then I ran the same test on my active PATA XP partition.

The benchmark shows the first RAID partition scores = 105mb/sec

and the PATA XP drive (seagate IDE / 160gb 8mb cache) as 49mb/sec which I thought looks very low.


Here is the problem, Windows shows the Drive size of the Volumes as the full size of the partitions as if they were not a striped array ..... ie, it shows my 20gb RAID volume as 40gb !

Basically, this raid setup took me about 5 minutes to set up, so I know it's not right yet, but it's weird and wonderful that the Disk I/O benched as you would expect a RAID 0 to perform, but the volume size is reading wrong in windows.



I mean the above striped partition should read as 69gb. not 138gb.

This is way too wierd, I just killed the 20gb RAID partition and re-built it to 500mb for a quick test.

I did a 500 mb folder transfer to the 500mb RAID partition in 60 seconds from my ATA drive, and then when I copied the same folder to my RAID 100 partition, it took 28 seconds. This is consistent with the expected speed of the striped disc..............

However, I then added another 120mb file to the 500mb partition, which is showing as a volume size of 1gb and is currently holding nearly 700mb of data.

IT'S IMPOSSIBLE !

[Mick_C]

I just installed the 2 new WD 200gb SATA II drives, I started configuring my bios for a raid setup, then thought, "hey, I'll just go into windows for the hack of it to see if the drives are there"

Well, they weren't , so I went to disk management and saw them in there as blank disks, and a requestor popped up asking me if I wanted to do a striped RAID volume! ...

Ummm, I just got told that you don't lose disk space in a RAID 0 config, so I guess that answers it?

Here's a little chart that shows disk waste according to cluster size. As you can see the difference can be quite a bit. BTW, did you set these partitions up as a Dynamic Disk? Or standard? Silly question, but it could make a difference in how the system sees the disk. You prolly already know this, but I include it anyway.

(From Help) Once converted, a dynamic disk will not contain basic volumes (primary partitions or logical drives), nor can it be accessed by MS-DOS, Windows 95, Windows 98, Windows Millennium Edition, Windows NT, or Windows XP Home Edition operating systems. Dynamic disks can only be accessed with Windows 2000 or Windows XP Professional. When you convert a basic disk to a dynamic disk, any existing partitions or logical drives on the basic disk become simple volumes on the dynamic disk. (End Quote)

I don't care for assumptions and I am assuming you use XP pro or 2K?   If not... nevermind.. LOL

[congo]

I thought I would lose 200gb because of the RAID 0 lol!

What a screw-up! Now I have an extremely fast 400gbs to play with!



Yes, I've created a dynamic disk.

Can I boot from that? Or do I need to set it up properly?

Going to try it now anyway.

XP pro

I have a vague impression that I should use  a 16k stripe size, lots of small files? Anyway, I checked out a throughput review, and 16k looked like, and was recommended as a good general size for high performance.

[Mick_C]

I thought I would lose 200gb because of the RAID 0 lol!
What a screw-up! Now I have an extremely fast 400gbs to play with!

Yes, I've created a dynamic disk.
Can I boot from that? Or do I need to set it up properly?

Here's some information you should read on Dynamic Disk Management and issues you might run into. BTW, Dynamic Disks fly and are great if you stay within the operational parameters.

[congo]

So, technically, a dynamic disk isn't a RAID? Or is it?

I mean, it's striping, but  where is the RAID controller? Is it really software driven RAID in WinXP?

What would be more efficient (less system/cpu overhead) and faster? As I said earlier, this showed 105mbs/sec in tests, I'm happy with that.

[Mick_C]

[quote]So, technically, a dynamic disk isn't a RAID? Or is it?

I mean, it's striping, but

[congo]

Thanks again for the reply.

I couldn't get the dynamic volume(s) as a boot drive.

I think it will work as long as the drives are not striped, which is what I want.

I've had a devil of a time getting set up. Firstly, my RAID documentation is badly written, with references to non-existent directories and files, (don't you hate that!), and badly written installation routines. I got stumped because I couldn't load the RAID drivers off my floppy during installation, turned out that the floppy was never written to, despite flashing lights and a normal writing time, seems the write protect tab was on and there was no warning/check in the raid driver install routine. It's been a while since I used a floppy drive

[4_Series_Scania]

You sure you've got enough hard drive space there mate?  :o

Thats a nice setup.

[Mick_C]

Thanks again for the reply.

I couldn't get the dynamic volume(s) as a boot drive...

I've had a devil of a time getting set up. Firstly, my RAID documentation is badly written, with references to non-existent directories and files, (don't you hate that!), and badly written installation routines...

Now, I'm having a blank screen at the final reboot before windows completes installation, this is after a missing windows file makes itself apparent near the beginning of the install process.

What flavor (brand) RAID card did you buy? I used Promise, and had a wee bit a trouble with signed drivers, but nothing like your going through.  ::)
Don't know where you are procedurally, but if you did try to install XP to the Dynamic Volume and can't boot you might need to start from scratch.  :-[ Gads I hope not! If this is the case, and you can access internet, read the this section first,

Make sure to read this! Moving XP to Dynamic Volume

http://support.microsoft.com/kb/283421/en-us

Looking forward to your success!  ;)
Mick

[congo]

Thanks again,

I do usually read what people post so there isn't any need to repeat yourself with me unomernot. (the repeated MS link), I did actually read it the first time and tried to set an MBR on the dynamic volume using the diskpart / retain command.

I had to experiment a bit to get the command syntax correct, I found it was not as easy to figure out as a lot of commands.......

Note that I said "figure out". I need to explain. When I started learning to fly, My CFI stressed the importance of how we tend to retain those first learnt concepts which are so important, they form our basic behaviour and attitudes towards what we are doing, hence, the initial exposure and instruction of a subject gets deeply imprinted on our minds and forms our "culture" towards the subject unless a stronger influence modifies that at some stage. There is a word for what I'm trying to describe, but it escapes me for the moment.

My PC culture was established by obtaining hardware in a remote area and with no telephone, internet or peer assistance, I had to figure everything out from scratch up to the point where I was writing my own scripts with and/or's etc.

So, that culture is so absolutely embedded, the last thing I think of is actually going and googling up command parameters or getting help to make it easy on myself..... sad isn't it?
This is a serious barrier to my learning capacity, as it takes me a lot longer to learn anything about PC's than most folks who just find the knowledge rather than try and "figure it out".

(Fortunately for me, my initial flight training was extremely sound and that serves me well.)

Back to my RAID array..... I was trying to attempt an installation of a dynamic, striped RAID volume without ANY hardware or third party software support. This was an unprecedented success until I wanted to boot and install from the array, then it became quite a different matter.

I admitted failure after an unusually short time, (my wife pressuring me to spend some time doing "other" jobs around here instead), so I just went ahead with the nvidia RAID solution bundled with my mainboard and it's drivers, I'm not sure how it works yet, but