Raid 1 and 5 Questions

[rory 0]

Okay so delving into this area, never set up any Raid before ..

want to learn now ..

 

First .. is this a good product ..?

http://www.lsilogic.com/storage_home/products_home/internal_raid/megaraid_sata/megaraid_sata_1506/index.html

Just using this card as an example as it is on Tiger's website.

 

Secondly, i have seen where Raid 1 is used for the OS using 2 HDDs, and Raid 5 for the Data HDDs ... would this require 2 seperate cards, say if I was using a total of up to 2 HDDs for the OS and 4 for the Data .. or can the one card work for all?

 

Also, what does this card plug into? One or more Sata inputs on the Mobo?

 

Lastly .. how do you set it up, or does it do it for you with its own installation disk?

 

Also, any recomendations on a PC Full ATX case that has 6 x Internal 3.5" Drive Bays, and / or a total of 10 x External 5.25" Drive Bays .. as to cooling etc .. these would all be Sata Drives I take it including the OS drives .. do you suggest hot swappable storage instead ..? If so how ..?

 

This would be the Case as an example ..

http://www.thermaltake.com/product/Chassis/fulltower/armor/va8000bws.asp

 

And this Mobo probably ..

http://www.gigabyte.com.tw/Products/Motherboard/Products_Overview.aspx?ProductID=2314&ProductName=GA-965P-DS3

 

Thanks

Rory

[Thomas 0]

Haven't played with the card before so I can't judge the quality. LSI is a middle tier company as far as averages go.

 

Depends on how smart the card is but two arrays generally takes two cards. It's going to take a PCI slot and the drives will connect directly to it. Usually it does a BIOS hook to let you do the set up prior to OS boot and it should have a driver disk. Which you will need if you do the OS on an array.

[CollinR 0]

RAID 1 is IMO better for a DVRs video drive then RAID 5. RAID 5 is better suited to database style duties rather then almost continous write.

 

 

Better hardware controllers open more options, duplexing RAID 1 even mirrors the HD controllers. Some allow nesting arrays like 1+0 which is about HD fail proof but is really only feasable with many disks.

 

 

Good read.

http://www.pcguide.com/ref/hdd/perf/raid/index.htm

 

 

 

Thats a sweet case $ though.

 

 

I would use this motherboard

http://www.abit-usa.com/products/mb/products.php?categories=1&model=326

 

I'm not ready to pay for the quad thing just yet, and Abit doesn't seem to have a board that supports it. I pretty much just buy Intel for work and Abit for play anymore.

[CSG 0]

Rory,

 

Look at the Asus mobo's, they have on-boad Sata raid. Saves you the cost of a seperate card.

 

Raid 1 just mirrors 2 disks.

 

Raid 5 allows for greater capacity because you can use 3 or more disks, although the usable space is less than the sum.

 

I don't think from a practical standpoint read/write speed is much different.

 

However, once you setup a raid, you can't undo it with reformatting the drives.

 

I've always stuck with Adaptec cards for drive controller or raid when not implemented on the mobo, but they prolly cost a few dollars more.

[CollinR 0]

RAID 5's parity storage is what makes it less then desirable for large compressed files.

[kensplace 0]

Dont forget any version of raid that requires multiple drives for the data to be written to (ie not just a mirror of the data, but spread over multiple drives) increases the risk of total downtime for the system should ONE of the multiple drives fail (which they will do at some point).

 

Instead of just replacing one drive and getting the system back up quickly you would either have to replace the one drive, and (if you can) rebuild the raid to recover the data, OR, replace ALL the drives to get it back up quickly and sort it out at leisure.

[CollinR 0]

Well I wouldn't say any version there are a few that can handle even multiple simulatinous drive failures and keep chugging along. This is how you get hot swap going. RAID 10 can do this but only IIRC 2 out of 4 drives 1 from each mirror max. With a good controller the machine can stay up while you swap them.

[kensplace 0]

Cool, didnt even realise raid had come that far, been a while since I last looked into it.

[rory 0]

Rory,

 

Look at the Asus mobo's, they have on-boad Sata raid. Saves you the cost of a seperate card.

 

Raid 1 just mirrors 2 disks.

 

Raid 5 allows for greater capacity because you can use 3 or more disks, although the usable space is less than the sum.

 

I don't think from a practical standpoint read/write speed is much different.

 

However, once you setup a raid, you can't undo it with reformatting the drives.

 

I've always stuck with Adaptec cards for drive controller or raid when not implemented on the mobo, but they prolly cost a few dollars more.

 

Ok thanks .. does this mobo do it though? Says it has Raid Function .. or is that just in the BIOS ..?

 

Also .. for say Raid 1 for 2 Drives and Raid 5 for 4 drives ... how would that work .. or still need a 6 port card like i posted above?

 

Remember this is all going to cost more than double what you guys pay for it .. time as i get it here .. so I wanna make sure its right the first time

 

thanks

Rory

[rory 0]

RAID 1 is IMO better for a DVRs video drive then RAID 5. RAID 5 is better suited to database style duties rather then almost continous write.

 

 

Better hardware controllers open more options, duplexing RAID 1 even mirrors the HD controllers. Some allow nesting arrays like 1+0 which is about HD fail proof but is really only feasable with many disks.

 

 

Good read.

http://www.pcguide.com/ref/hdd/perf/raid/index.htm

 

 

 

Thats a sweet case $ though.

 

 

I would use this motherboard

http://www.abit-usa.com/products/mb/products.php?categories=1&model=326

 

I'm not ready to pay for the quad thing just yet, and Abit doesn't seem to have a board that supports it. I pretty much just buy Intel for work and Abit for play anymore.

 

thanks .. this is primarily for a DVR ... seen the specs online for others they have Raid 1 on 2 Drives, and then 4 drives (actually 6 in some cases) as Raid 5 ..

 

I think im still lost though ..

[CollinR 0]

I look at Abit and Asus as almost the same... Top quality, uncompromised performance with good reliablity.

 

I wouldn't do the quad CPU thing just yet especially not with a DVR, keep the HT issues in mind x2. Often the bleeding edge means getting cut.

 

I would consider one of their on board solutions however a dedicated hardware controller (Adaptec as mention is my fav too) is probably better.

[rory 0]

I look at Abit and Asus as almost the same... Top quality, uncompromised performance with good reliablity.

 

I wouldn't do the quad CPU thing just yet especially not with a DVR, keep the HT issues in mind x2. Often the bleeding edge means getting cut.

 

I would consider one of their on board solutions however a dedicated hardware controller (Adaptec as mention is my fav too) is probably better.

 

whats the quad CPU thing?

[rory 0]

ok .. so lets say I want to use Hot Swap HDDs for the video .. 4 of them .. and do Raid 1 for the OS and DVR software ... Raid 1 would be okay on SATA-150's .. (40/80GB) ?

 

Do the Hot Swaps need to be Raid 5?

[CollinR 0]

Dunno where the quad processor came from. Must be seeing things.

 

 

RAID on a DVR's OS drive is about pointless, just ghost the drive once you have it all setup. It shouldn't contain any real info other then the OS and DVR software. Better bet is embedding the OS on a solid state drive.

 

I'm pretty sure RAID 10 is entry into hotswap configurations, could be wrong though.

 

SATA is 1 port 1 harddrive so no matter what you do you'll need a port for every disk. The controller should specify if it can handle multiple arrays on their card (your example)

[rory 0]

ok .. just looking to compete ... but mostly for information purposes .. see lots of Raid 5 and Raid 1 stuff with Geo out there .. they say Raid 1 means it makes a copy of the OS so if one HDD goes down you just swap the HDDs?

[CollinR 0]

In RAID 1 when a disk fails it ~should~ seamlessly fall back to the remaining drive. ****SHOULD**** many don't they blue screen and successfully reboot on the remaining drive.

 

If you were to hotswap that drive the controller would try to instantly mirror the good one to it. * see above * If you have 20 GB of data it's not such a big deal but in a larger array it'll take time to read from one and then write to the other. The result is a major system impact during that time, you probably won't have enough bandwidth left to operate.

 

Look into embedding the OS on a solid state drive, then you won't need RAID and you can concentrate on the data storage array and ensuring their evidence survives.

 

Does Geovision offer an embedded OS chip?

 

You could do the on board RAID of 2 40GB drives to RAID 1. Might be cost effective since those drives are dirt cheap now.

 

I can't believe microshaft hasn't found a way to get you for 2 licenses for that.

[sal 0]

Avermedia has a DOM solution at this time.

 

 

http://digitalwatchguard.com/securitycameras/pc/viewPrd.asp?idcategory=553&idproduct=4152

[CollinR 0]

Avermedia has a DOM solution at this time.

 

 

http://digitalwatchguard.com/securitycameras/pc/viewPrd.asp?idcategory=553&idproduct=4152

 

 

Can you edit their disk image? Do you happen to have a DOM you can get more pics of? They often have a switch on the DOM to prevent writing to it. I wish I had checked this before I called Alex this morning.

[sal 0]

The DOM unit is an industrial grade disk on module device (1 Gigabyte in size) and the whole image cannot be edited from other software.

 

There is no switch on the DOM to prevent writing because the software will still need to write to it especially DVR settings and XP Embedded settings such as IP address, etc.

[CollinR 0]

I did some digging to see what I could find.

 

 

http://dom.pqimemory.com/DOMProduct/ProductHome.php?pid=7&click=1

 

Looks like it, and no write protection at all.

 

 

 

The good.

 

If you have enough skill you can hack the image however you like. This is a major bonus to me as I can't every seem to leave anything un tinkered.

 

The bad.

 

Having a hardware lock on the DOM assures that the OS has been configured correctly to never write to the disk once the installation is complete (excellent example on the IP address). These DOMs are extremely limited on writes so if the windows swap file or cache are written to the DOM often it will die, also hardware locking it reduces the possiblity of corrputing the data for the OS and boot.

[sal 0]

nicely done

[rory 0]

I wonder if you can copy the image to another DOM that can be locked .. but first setup all the IP info, etc .. unless they set the page file to the DOM and not the attached HDDs? Course if you have that kind of control, you could always move all the locations of files that are constantly changed .. but then Avermedia software itself may write changes (settings) to the DOM so that would not work ...

[CollinR 0]

I wonder if you can copy the image to another DOM that can be locked .. but first setup all the IP info, etc .. unless they set the page file to the DOM and not the attached HDDs? Course if you have that kind of control, you could always move all the locations of files that are constantly changed .. but then Avermedia software itself may write changes (settings) to the DOM so that would not work ...

 

 

Yes you can do all of that, and Avermedia surely has their software presetup to not write to the disk after installation. Most have the system create a RAM drive that stores all the stuff the OS needs to read/write during operation, then it's all dumped on reboot.

 

It would take some time to really get their original disk image figured out.

[rory 0]

so far the only downside i see is they dont have an SDK (according to one of their reps that is on this forum), but i wonder if there are any public procedures in the ActiveX that can be utilized ... anyone got a demo link to an online site using the ActiveX, that I can take a look at?

[Oxide.Blu 0]

I’ll toss out what I did for my PC based DVR, and why, and hopefully it will dispel any misconceptions about what RAID can/can't do.

 

I opted for a newer Intel 945G board because of (a) the embedded Matrix RAID (1, 2, and 5), and (b) the embedded graphics driver has overlay …meaning I did not need to buy a video card.

 

My DVR is:

 

mother board

DVR card

pair of SATA HDDs.

 

That’s it!!! Less h/w means less heat means less fan noise means a quieter DVR. Oh, there is a CD/DVD-RW drive in it collecting dust, too.

 

I set up the pair of 250gb HDDs by partitioning 30gb off the top of each HDD for the Win XP operating system and “future applicationsâ€