Sata Raid 0 with WD Raptor

[rory 0]

this is for a home PC .. any recommendations on a decent not too expensive Card to hook up 2 or 4 of the 74GB Raptors (10K rpm) drives in Raid 0? Mobo doesnt have onboard raid, looking for additional speed.

 

Remember ive never done any raid before so be gentle ..

 

This is the case im using ..

 

see the hard drive cage there, the top space is taken by a Card Reader drive .. so it leaves me 4 spaces for Hard Drives, but would 4x 10,000 rpm drives get too hot being that close to each other? If i add another fan in one of the slots near the PCI spaces, and direct that air on the hard drives, would that help enough? There are now 3 fans already, one right there at the front pushing air in, a 120mm rear case exhaust fan, and one on the Side Panel CPU shute, just for the CPU though.

 

Im going for performance over anything else in this case .. and read that 4 drives in Raid 0 is the fastest . .. but for checking email, Skype, and a little MS word, Nortons installed also, which is really all the client uses .. could 2 drives suffice and still be much faster than a normal drive setup?

 

Thanks

Rory

[Jasper 0]

I don't recommend RAID 0 unless you really need it. One drive dies and you lose all your data.

 

Is this for a security system? Your own personal system?

 

Any more than 3 drives in a RAID 0 array is a waste.

 

Why not one 150GB WD Raptor?

 

Also Seagates new 750GB Perpendicular drive is almost as fast as a raptor.

 

If you want pure performance though the 150GB Raptor is your best bet.

 

As far as heat, as long as you have good airflow going through the PC should be ok. I removed one of the front panels of the front of my PC to get more cooling. I took readings with a thermometer.

 

The drives being close together should not be an issue as long as air can pass between the drives.

Edited April 18, 2007 by Guest

[rory 0]

this is for a home PC for a client .. she has a Core 2 Duo 2.6 with 2GB DDR2 667 etc .. just want to see if we can get more speed out of it .. loosing data isnt an issue .. its just for email and other basic use, and she backs up alot to an external USB drive .. so its primarily for speed. Size isnt really an issue also as all her docs only total like 20MB

[Jasper 0]

this is for a home PC for a client .. she has a Core 2 Duo 2.6 with 2GB DDR2 667 etc .. just want to see if we can get more speed out of it .. loosing data isnt an issue .. its just for email and other basic use, and she backs up alot to an external USB drive .. so its primarily for speed. Size isnt really an issue also as all her docs only total like 20MB

 

In her case a 10K RPM drive should do the trick then. Or two of them in a RAID 0 if she really wants the snappiest response.

 

Sounds like a new system so it probably already has SATA on the motherboard? If not she can buy a card for a PCI slot or Express slot that supports RAID if her system doesn't.

[rory 0]

In her case a 10K RPM drive should do the trick then. Or two of them in a RAID 0 if she really wants the snappiest response.

 

Sounds like a new system so it probably already has SATA on the motherboard? If not she can buy a card for a PCI slot or Express slot that supports RAID if her system doesn't.

 

yes she has the $$ and wants the fastest ... well it is fast now .. but id like to make it faster anyway

 

According to this article .. the more HDDs the faster it gets with Raid 0?

http://pcpitstop.com/news/maxpc/disk.asp

[Jasper 0]

In her case a 10K RPM drive should do the trick then. Or two of them in a RAID 0 if she really wants the snappiest response.

 

Sounds like a new system so it probably already has SATA on the motherboard? If not she can buy a card for a PCI slot or Express slot that supports RAID if her system doesn't.

 

yes she has the $$ and wants the fastest ... well it is fast now .. but id like to make it faster anyway

 

According to this article .. the more HDDs the faster it gets with Raid 0?

http://pcpitstop.com/news/maxpc/disk.asp

 

If you have 4 slow hard drives it might take that many to saturate the BUS.

 

What you have to consider is the max sustained throughput of the drives that are mirrored. The reason is because of the BUS bottleneck which limits you to moving only 133MBps accross the BUS to the CPU.

 

You will have to check on the Raptors max sustained throughput, but I am guessing it is at least 60MBps. So if you have two of these in a RAID 0 mirror you are essentially moving 120+MBps of data accross the BUS.

 

So you see once you have saturated the BUS with data it doesn't matter if you have a 3rd or 4th drive in the arrary because it won't do you any good.

 

Now I am thinking about the PCI BUS, but I have to remember that the newer PCI Express BUS does not have this limitation so you would be correct.

[rory 0]

ok .. so basically though, using 2 drives, it would be twice as fast as a regular setup right? If so then that would suffice for what she does .. that would make a big difference either way .. it seems?

 

Any ideas on PCI Cards, maybe just Adaptec 2 port or would a cheapo one work?

 

The PCIex16 video card is so close to the PCIex1 slot not sure if that would work well to usea PCIe controller card.

[Jasper 0]

ok .. so basically though, using 2 drives, it would be twice as fast as a regular setup right? If so then that would suffice for what she does .. that would make a big difference either way .. it seems?

 

Any ideas on PCI Cards, maybe just Adaptec 2 port or would a cheapo one work?

 

The PCIex16 video card is so close to the PCIex1 slot not sure if that would work well to usea PCIe controller card.

 

I think 2 10K drives is overkill for her, but if she wants speed, 2 drives mirrored will make a big difference. If she is working with primarily small files then she might not even notice a difference over 1 fast one though.

 

One fast drive with high burst speed will get the emails and other small files open quickly.

 

Mirrored drives are typically used when processing huge files like video. That is when she will notice the faster speed is when moving large files.

 

Regarding the card, that is a personal choice. Depends one what type of RAID support you want. Some have RAID 0 only. I have a combo card that gave me SATA, Firewire 400, 800 and USB with RAID 0 support.

[CollinR 0]

4 drives in AID 0 (doesn't deserve an R) is just begging for a problem, if you are going to be providing any type of warantee or you care about your reputation don't do it that way.

 

As was mentioned one hiccup and it's rebuilding the array and reimaging the box. It's 4 times more likely to happen compared to a non-AIDed configuration.

 

1st surfing, email, Skype, MS Word = jack crap HD usage, so no gain however big $.

 

 

Swap motherboards and get some decent RAM, quite possibly a better CPU. Way less money and way more benfit realized. You might get crazy enough and use a server board, if you can trim her install enough you can use it in a RAM drive. RAM is way way faster then any HD.

 

What is the latency of the operating memory? This will make as much of a difference as anything else.

 

 

Also strip the OS to little more then what we do with DVRs, reduce overhead at almost all costs.

 

If you add a fan on the PCI side directed at the HDs you will be worse off, direct it outside the case.

[Jasper 0]

4 drives in AID 0 (doesn't deserve an R) is just begging for a problem, if you are going to be providing any type of warantee or you care about your reputation don't do it that way.

 

As was mentioned one hiccup and it's rebuilding the array and reimaging the box. It's 4 times more likely to happen compared to a non-AIDed configuration.

 

1st surfing, email, Skype, MS Word = jack crap HD usage, so no gain however big $.

 

 

Swap motherboards and get some decent RAM, quite possibly a better CPU. Way less money and way more benfit realized. You might get crazy enough and use a server board, if you can trim her install enough you can use it in a RAM drive. RAM is way way faster then any HD.

 

What is the latency of the operating memory? This will make as much of a difference as anything else.

 

 

Also strip the OS to little more then what we do with DVRs, reduce overhead at almost all costs.

 

If you add a fan on the PCI side directed at the HDs you will be worse off, direct it outside the case.

 

I agree with you about 4 drive RAID 0 is just asking for problems. I have a Lacie 500GB mirrored drive. It was fast, was, until one of the drives failed.

 

The CPU and 2GB of RAM is plenty, even for VISTA. She will definately notice a performance boost anytime she launches a program. They will load much faster.

 

The hard drive is still the biggest bottleneck.

[CollinR 0]

BTW where you been Jasper?

[rory 0]

Trust me .. software wise its tweaked as much as I could .. also remember she is running all the Nortons software on the market .. dont ask .. she just has a thing for Nortons .. so though nothing else she uses really effects the speed, Nortons is always there, well there is Office 2007 also, but that loads fast on that PC. She likes all the XP graphics also ..

 

All brand new so no need to swap anything right now .. when the quad core drops in price we will change the mobo and go quad core, probably 1066 memory also if its stable at that point if not 800 .. but for now its Mushkin Dual Channel DDR2-667 2GB Memory, and a Core 2 Duo 2.6 (E6700) the one just below the Quad Core.

 

As to cooling, its great right now, CPU and mobo in the 30's. 1x 120mm rear exhaust fan and 1x 80mm front inward fan, and 1x 80mm fan on the CPU mounted to the side panel.

 

There is no warranty by myself, it is all purchased direct by her from the US .. I just built it .. something goes wrong i fix it and I get paid is all ..

 

As to rebuilding the raid etc .. with 1 hard drive in normal setup, one hiccup and the same issue exists anyway .. so the issue is not that, the issue is what will give the fastest performance on the HDD side of things, leaving the rest as is .. Course the biggest issue is how to get those 10K drives here from the US without the usual damage the other hard drives have incurred during shipping

Edited April 18, 2007 by Guest

[rory 0]

I think 2 10K drives is overkill for her.

 

she buys $10K TVs, has 30 workmen at her home on any given day doing this project and that project .. so overkill is yeah ... thats what she likes

[Jasper 0]

BTW where you been Jasper?

 

I've been real sick for a long time and busy on top of it.

 

Rory, if she's willing to buy the hard drives than what the hell.

 

If she only has 20MB of data and she wants programs to launch fast, etc. Then go for it.

 

But like Collin said each hard drive added increases the risk of her losing her system. But if she just needs restore back to before the failure maybe you should get here a seperate drive for her to backup her RAID drives too using Acronis TrueImage or something similar.

Edited April 18, 2007 by Guest

[rory 0]

I've been real sick for a long time and busy on top of it.

 

Rory, if she's willing to buy the hard drives than what the hell.

 

If she only has 20MB of data and she wants programs to launch fast, etc. Then go for it.

 

But like Collin said each hard drive added increases the risk of losing her system. But if she just needs restore a clean system maybe you should get here a seperate drive for her to backup her RAID drives too.

 

she has an external USB drive she backs up to now.

I already image the drive once everything is loaded and working .. and back that up also.

[Jasper 0]

The extra hard drive would be for quickly restoring her system back to its pre-failure state. Otherwise it is a full reinstall by CD or DVD's. And then all the apps, etc.

 

Remember RAID 0 offers no data protection. It is only for speed.

 

Your maintaining an OS image for her? If that is the case then your set.

 

Also it allows you to offer that service to her. RAID 0 with 4 drives it is?

[rory 0]

nah just created an image using a program called SnapShot .. then I can just restore a new Hard Drive or the same one, when she needs a fresh install ..

 

other than that, manual install (kind of) im down to 1 hour 30 minutes tops now .. installing XP with SP2 and all the apps .. tweaked

 

But yeah i see what you mean .. will think it over .. thanks guys.

[rory 0]

quick question .. with raid 0 ...

 

if you have an image already .. do you just restore that image to the hard drive that will be set up as a primary drive .. then put the 2 drives in, go into windows XP (on the drive that had the image restored to it) and load some Raid 0 drivers or config program to create the arrays, or is that done before windows? In other words can the data stay intact and then you just create the raid arrays with the primary hard drive already loaded with XP, without loosing any data?

 

thanks .. as you can see ive never had more than 1 hard drive personally

[Jasper 0]

quick question .. with raid 0 ...

 

if you have an image already .. do you just restore that image to the hard drive that will be set up as a primary drive .. then put the 2 drives in, go into windows XP (on the drive that had the image restored to it) and load some Raid 0 drivers or config program to create the arrays, or is that done before windows? In other words can the data stay intact and then you just create the raid arrays with the primary hard drive already loaded with XP, without loosing any data?

 

thanks .. as you can see ive never had more than 1 hard drive personally

 

Typically the RAID controller will have software in its firmware that will allow you to enter a menu at boot up. If one of the drives fail you usually can use the utility of the RAID controller to break the current RAID.

 

You then place your restored drive as the primary as you suggested. Reboot, enter the RAID controller software and rebuild the array using the utility program supplied by the RAID card vendor.

[survtech 0]

quick question .. with raid 0 ...

 

if you have an image already .. do you just restore that image to the hard drive that will be set up as a primary drive .. then put the 2 drives in, go into windows XP (on the drive that had the image restored to it) and load some Raid 0 drivers or config program to create the arrays, or is that done before windows? In other words can the data stay intact and then you just create the raid arrays with the primary hard drive already loaded with XP, without loosing any data?

 

thanks .. as you can see ive never had more than 1 hard drive personally

With XP Pro or above, you can just load your O/S and data on one drive, go to Windows Disk Management, right click on the primary drive, and then select mirror. It's a very simple process.

[kmurrey 0]

I am curious what you came up with this.

 

If you are truly wanted redudancy than you want to use RAID 5 with 3 drives. In the event one drive dies, you replace it, and rebuild the raid set.

 

I would just use SATA drives with a true RAID controller.

 

RAID 0 is just mirroring, it is faster - but there is no redudancy.

 

Also - here is an excellent rundown on RAID Levels.

 

http://www.acnc.com/04_01_00.html

 

As a network dude for over 19 years - we only ran RAID 5 in our server based applications. Sometimes I would run Raid 1 for the OS and then Raid 5 on the data side.

[rory 0]

neither, client was happy as it was

 

Ill try raid 0 later on myself though, as im primarily into speed, have external drives for backup.

[woodyads 0]

Raid stands for redundant array of independent drives. RAID 0 is not true RAID as there is no redundancy. Cheers Colin right on the mark there. Techniques for utilising arrays of drives are mirroring, striping and parity. RAID 0 is not mirroring its striping, with no parity (kmurrey you probably meant this above).

 

RAID 0 = Stripe

RAID 1 = Mirror

RAID 4 = Stripe with parity (dedicated parity disk) (nobody uses this)

RAID 5 = Stripe with distributed parity

RAID 1/0 or 10 = Mirrored Stripe. (High redundancy quick rebuild very fast)

 

Stripe for speed

Mirror for redundancy

Parity for cheep redundancy.

 

Parity has a calculation overhead. A slow raid card or OS RAID 5 will kill the machine.

Mirroring in theory writes at the same speed but can read like a stripe. But has the cost of halving the disk space.

Stripe is fast and cheep but has no redundancy and increases the chances of data loss. If you have 4 disks you have 4x the speed but you only need to loose 1 drive to kill all the data

RAID 4 wastes disk space

RAID 5 use one of several different algorithms depending on the card or OS.

 

Cards. They vary, not all are capable of what you are told RAID can give you, auto hot spare, live rebuild etc. Speed may also vary. SCSI is faster than SATA. SCSI has many little tricks up its sleeve for speed. Like spindle sync which is advantageous for video playback. But this is rare and the card and drives must be matched. I have only built one spindle sync machine that was a dedicated post production machine, cost about $60k, a genuine case of RAID 0. Today speed and RAID is not what it seems because of the large amount of cash on the drives RAID may not be any quicker in many application or if drives and card mismatch the application. RAID cards tend guarantee reliability not speed. As time passes newer drive will be slowed down by old cards. This can happen in a period of months.

 

CCTV. Tend to write several video streams to on array of disks. So you have a constant write happening, when you read you read one or many streams, jumping between the streams or between the read and the write stream. SCSI has out of order execution, this could possibly help in performance, I am not to sure if ATA now has this I think it is included but not to sure if it is as smart as SCSI. Without a doubt there would be some card and disk testing required to find what's best for CCTV servers. I can't say exactly what it is but the safe way to go for a large setup is to use a NVR SQL server for admin and push all your streams to SANS. (I am talking big installation here). Because of the nature of the streams and how they are recalled on disc I would suspect speed issues from multiple playback being the first bottleneck. So limiting the number of cameras or streams per SANS would be the trick. Just looking from a design bang for buck low maintainance scalability perspective the most efficient way to set up a decent size CCVT is on an existing well built SQL server using SANS for video storage.

 

Drive terminology, these definition get clouded once you start clustering and creating virtual drives or partitions over separate network storage. So I will use these definitions from the view of a single server.

Virtual Disk = A group of drives that appear as one

Physical partition = a partition that may consist of many disks but is physical independent of other partitions.

Logical partition = physical partition or drive may have many logical partitions.

 

How to allocate drive in your server. Rory even though you are not looking at a fully blown server you can still imitate this.

First Physical Partition. Two hard drive in RAID 1 (mirrored) with 3 logical partitions

1 for operating system

2 for Swap file

3 for SQL Log files, and log files

 

Second Physical Partition. Three or more drives in a RAID 5 configuration with 2 or more partitions

1 for install files and sever specific applications

2 for network share, to move admin file to and from the sever

3 for data (SQL Data)

4 for Video Stream Data

 

In a normal SQL build 4 wouldn't exist and 1 and 2 can be combined

In a dedicated CCTV NVR 1,2,3 can be combined as they are small

In an Enterprise CCTV NVR I would use all 4 partitions however 4 might end up on SANS

 

For SQL.

the SQL data and the SQL log files need to go on separate physical partitions. So if your drives with SQL Data die you can rebuild from last backup then run the log files that will bring you back up to the minute. I am currently specking a high transaction SQL server and we are toying with a separate arrays for the SQL Log files, and the DBtemp file to enhance speed. CCTV NVR's hardly use the SQL database so this would be overkill for this application.

 

Your small home machine

Put your OS and swap file on one disk along with your database etc (See notes about separating database log files from database below)

Put your Video on the RAID 0,1,5 fast disks (with database log files or Database but not both)

 

Partition your OS drive 3 ways so swap file and logs are on their own partitions. Otherwise the logs can grow and stall your OS drive and bring the machine down. Yes you do setup logs so this doesn't happen but I have attended more than one server where the logs have gone crazy and bought the server down due poor build standards. Why set up this way, think about the disk head. You don't want them jumping from swap file to video steam, then writing your database

 

By the way on a NVR your live stream buy passes the server so there is no overhead for viewing. I never bothered looking deeply into DVR's but you would have to work out if there are DMA issues with the server. Ineffective use of DMA controllers would mean the CPU could get hit up for interrupts. I am sure this has been worked out but if not there could be some CPU could come under fire.

 

While some of the above setups may look expensive you can see how you can emulate this quite simply and cheeply. There is more to backing up datbases than just tape and buy using two physical partition (disks) to store your Data and logs separately you bring your backups up to the minute. Hope this is helpful.

[rory 0]

thanks guys ... and woodyads lots of good info there

 

Though in my case it is not for back up, just speed ..

 

Ill see if we can make this a sticky though for future work ..

 

thanks.

Rory

[woodyads 0]

I think a killer in your case Rory is if you are going to try the Raptor and RAID 0 then definitely throw in a separate OS drive with swap file on it.

 

Reason

If you set up RAID 0 drives with OS and swap file (virtual memory) then your drives will be jumping from the stream to the virtual memory. you could be better off with no Raptor and putting OS and swap file on one drive and streams on the other. You loose more time moving heads than writing. So get your Raptor 2 high speed hard drives for streaming and cheaper hard drive for the OS and swap file.

 

Or and I haven't put too much thought into this. I am sure most CCTV software could be set up this way. Keep the two stream drives separate and send separate cameras to each drive. Put them on separate controllers (might not be necessary) . This could give better performance on playback than a RAID 0. Furthermore you could bring the streams in on separate network cards. This would reduce the fragmentation of the streaming files and you will only use one disk for review when reviewing one stream so the other streaming disk will be left alone.

 

Drive selection.

You would need to test to verify. Cache may be more important than disc speed. As head jumping is you biggest overhead, cache on a hard drive works in different ways, one method is to grab the entire track cause chances are the next drive request will come from the same area. With streaming this is the case. Granted that faster hard drives usually have more cache than slower drives. But scrutinise between different brands.

 

I only refer to reviewing as a problem because if you are having problems with recording you are not going to have a hope reviewing and recording at the same time.

 

Cheers