Nubee needs advice

[DigitalDivide]

Hi, I'm a nubee to this and have a quite a few questions I hope someone doesn't

mind answering.

 

I have the following hardware in my existing server

ASUS P5PL2 MB - http://www.asus.com/products4.aspx?modelmenu=2&model=941&l1=3&l2=11&l3=244

Intel Celeron D

Antec P180 Case - http://www.antec.com/us/productDetails.php?ProdID=81800

True Power 500W PS

1GB RAM

1 300GB SATA2 Drive

2x160GB SATA Drives

1x160GB IDE Drive

 

Will I have any problems with my hardware?  My MB has 4 onboard SATA

connections.  If I install 3 Data drives and one 500GB SATA drive as parity

using the onboard SATA connections, will I be okay?

 

What do I do if I want to add another drive?  Do I have to buy the Promise

Controller?  Will it be simple to add this to the Unraid?

 

My 3 data drives contain data (full DVD's and movies) on them.  Can the Unraid

be setup using existing drives without losing the data?  I'm assuming I can't

because the drives have to be formatted with the file system Unraid uses.  If I

buy two new 500GB drives, and setup the Unraid using one as parity and the other

as data, can I start copying all the data from one of my other drives to the new

data drive, then once my existing older data drive is empty, simply format it

and add it to the unraid?  Then repeat the process by copying data from the

older drive with data to the older drive that's now in the array? Or do I need

to start with 3 blank drives, one for parity and two for data?

 

Any help would be appreciated.

 

Thanks!

[Two Wire]

Here is what I did. First, I went into the MB bios to see if I could get a boot from a USB port. I had some old MB's lying around which I tried and could not get a boot from USB. I did not damage the flash drive, which I did not think I would, by the way. I purchased the ASUS P5PE-VN to solve this problem. I am using the free version of Unraid to try my system out. Next, I connected a 300 GB HD to the primary IDE port (using cable select) and one 500 GB serial drive on one of the two serial ports. I am using the serial port for my parity drive. I fired it up and went to the management page to set up the hard drives. I think you can select any HD to be the parity drive and the others to be data disks. Since the MB has two IDE ports (2 channels each) and two serial ports, I can have a total 6 drives. If I need more storage, I would simply add a Promise controller card (IDE or serial, depending on your preference). Third, after the disks were formated, I used Windows Explorer to copy and paste my data from my local hard drives, to the Unraid Server. It did not take long to transfer the data, but developing parity took some time.

 

This was a pleasent experience for me and everything is working great. I plan on upgrading to a more featured version soon.

 

I think you just need to jump in and try what you have. From What I see in you list you should be good to go.

[DigitalDivide]

If I download the free version, can I create a flash boot device without harming my existing Windows XP system?  While making the boot flash device it doesn't erase or format anything does it?  I don't want to lose what I have without knowing for sure that I will be able to boot off the flash.

[limetech]

If I download the free version, can I create a flash boot device without harming my existing Windows XP system?  While making the boot flash device it doesn't erase or format anything does it?  I don't want to lose what I have without knowing for sure that I will be able to boot off the flash.

 

After you plug a Flash into your Windows PC let it 'cook' for awhile until you know Windows has completed the hot-plug process.  Usually at the end Windows will automatically open an explorer window showing you the contents of the Flash device.  If the Flash came with some pre-installed software, there may also be some auto-started applications you'll want to close.

 

At this point what I ususally do is close any windows that were automatically opened and then click on 'My Computer'.  You should see the Flash listed as a device in there.  Take note of the drive letter that Windows assigned to the Flash.  Now right-clilck the flash and format it.

 

Make sure when you run the 'syslinux' program you use the correct drive letter windows assigned to the Flash.

 

When you are ready to try to boot the Flash you will want to examine your motherboard bios.  I recommend you keep track of anything you change.  You should only need to change the boot device.

 

You can boot unRAID with all your drives installed, including your Windows drive.  Nothing will be written to any of your hard drives unless you bring up the Management Utility and click on the 'Start' button - actually still nothing will be done yet because you first have to go assign the hard drives on the Devices page.  It doesn't hurt though to pull the power plug on your Windows C drive just be to safe 

[DigitalDivide]

If I just want to run a test to see if my pc will boot via the flash, will a 32mb flash device be good enough?  If that works I can then always buy a 128MB flash device.

 

Also, one other question.  I just want to be clear on this.  If I have two data drives filled with movies and music, and one parity drive, and one of the data drives fails.  I can take out the bad drive, pop in a blank one, and the data that was on the bad drive will be restored??  I don't lose a thing? 

 

How is it that a number of large companies I know that use Raid 5, don't use anything resembling Unraid?  By that I mean they have to use the same drives, same size.  Also when adding a new drive, they have to rebuild the array.  Nothing as simple as Unraid.  Seems kinda odd.

[Joe L.]

If I just want to run a test to see if my pc will boot via the flash, will a 32mb flash device be good enough?  If that works I can then always buy a 128MB flash device.

It appears as if the files in release 3 are a bit over 26 Meg.  I would think you could try it with a 32 Meg flash drive (must be pretty old, might be USB 1.0 so it might boot slowly)

 

Also, one other question.  I just want to be clear on this.  If I have two data drives filled with movies and music, and one parity drive, and one of the data drives fails.  I can take out the bad drive, pop in a blank one, and the data that was on the bad drive will be restored??  I don't lose a thing? 

Correct.  The data on the bad drive will be rebuilt.

 

How is it that a number of large companies I know that use Raid 5, don't use anything resembling Unraid?  By that I mean they have to use the same drives, same size.  Also when adding a new drive, they have to rebuild the array.  Nothing as simple as Unraid.  Seems kinda odd.

Raid 5 requires all the drives to be the same exact size (easiest when all the same brand and model), unRaid (A modified version of Raid 4) requires the parity drive be bigger than, or equal in size to any of the other drives. It is more flexible, and far better as we incrementally grow the array as disk drives go on sale, something corporate arrays don't usually do.  Raid5 and unRaid are similar, but serve different audiences.

 

Both Raid5 and unRaid require you to rebuild a failed drive. (unRaid still lets you read and write to the "failed" drive even while it is being rebuilt.  With 750Gig drives the rebuild will take 8 or more hours.)

 

Joe L.

[limetech]

If I just want to run a test to see if my pc will boot via the flash, will a 32mb flash device be good enough?  If that works I can then always buy a 128MB flash device.

 

32MB is pretty tight - real easy to test - just try it!  Also a new USB2.0 512MB flash (and even larger) can be had for less than 20 bucks.

 

Also, one other question.  I just want to be clear on this.  If I have two data drives filled with movies and music, and one parity drive, and one of the data drives fails.  I can take out the bad drive, pop in a blank one, and the data that was on the bad drive will be restored??  I don't lose a thing?

 

That's correct. But with all things in life nothing's perfect.  If your other data disk(s) or parity disk fails before you have a chance to rebuild the already failed disk, then you will lose the data of both disks [but with unRAID, not the data of the other surviving data disks].  Also, if one of the other disks experiences an unrecoverable read error during the rebuild, then the corresponding block on the new disk will not be reconstructed properly - this may or may not cause data loss.  BTW, these caveats are not unRAID-specific, all RAID systems have these vulnerabilities (though RAID-6 is less vulnerable).

 

You can easily test this capability.  Once you have an unRAID system up and running with valid parity, you can power down, remove a disk, power up and Start - unRAID will notice the missing disk and disable it.  Now you can power down, plug in a new disk, power up and Start - unRAID will notice the new disk and start a parity-reconstruction.  Then you can examine if the data was restored correctly.

 

Notice we say 'power down' before removing/installing hard drives - due to h/w IDE systems will never support hot swap - but a future release of unRAID will support SATA hot swap, though not at present.

 

How is it that a number of large companies I know that use Raid 5, don't use anything resembling Unraid?  By that I mean they have to use the same drives, same size.  Also when adding a new drive, they have to rebuild the array.  Nothing as simple as Unraid.  Seems kinda odd.

 

It's because in traditional RAID systems the data is striped across all the drives.  For more discussion on this, read our technology overview.

 

unRAID is superior from the standpoint of configurability, expandability, and lower power use, but suffers from a key disadvantage (which we have never tried to hide): inferior write performance.  This is due to the fact that unRAID does not stripe data across multiple drives (hence no bandwidth increase), and it has a single parity disk (hence no writes in parallel).

 

The question you have to ask yourself is, "Can I live with the reduced write perfromance (relative to other RAID systems) in my application?"  For many media storage applications the answer is "yes - no problem".  Why is this true?  Consider the source of most media data: DVD/CD drives, tuner cards, video cameras, digital cameras, etc.  None of these devices have particularly high bandwidth.  If you capture your media directly from it's source and store it on an unRAID system, what difference does it make if the write performance is 15MB/sec or 80MB/sec (or higher) if your source is dribbing the data out at 10MB/sec or less?

 

That said, we have some code in the works which will significantly help unRAID write peformance.

 

[DigitalDivide]

Sorry for all the questions but I really want to make sure I have a good handle on this before starting down this path.  Thanks for the info so far!

 

Okay I think I will go out and buy a new USB Flash Device before I buy my two 500GB drives.  One last question...for now...If my usb device is accidently yanked out or simply dies, do I loose my datal?  Can I simply make a copy of my usb device so that if one dies, I simply unload it and pop in the new one?

[DigitalDivide]

I think I read somewhere that you can't backup your USB flash device.  But I still need to understand what happens if it accidently dies or gets yanked out of the drive by accident?

[mutant_matt]

Make sure you purchase a 2-flash license so that you have a backup flash ready to go if one fails.  That way, you won't have any down time.

 

HTH!

 

Matt