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Newbie Question - Minimum Hard Drives to get Started?

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Hi,

 

Following on from my earlier thread testing the P5B-E motherboard, I have bought a 500GB SATA drive, and I am now trying to setup my first working unRAID system to test.

 

I'm using the 4.0beta-7 with the following hardware:

 

Asustek P5B-E mobo with 6 x onboard ICH8R SATA (+2 JMicron SATA)

Onboard Attansic L1 GigE

Celeron D 3.06Ghz 533FSB 512M Cache

1GB DDR2 DRAM (2x 512MB G.Skill CL4)

Cheap as I could find PCI-e Video card (XFX NVidia 7100GS)

Seagate 500GB 16MB Cache SATA Drive

 

My question is, how many hard drives are needed to get started?

 

Seems like a simple question, but I can't find an answer anywhere, only a reference to not needing a parity drive.  Although, I know that for a normal RAID5 system, you need 3 drives to get started.

 

Based on the post mentioning that you don't need a parity drive, I assumed I should be able to startup unRAID with only a single drive (allocated as Data Disk 1), with no parity drive allocated yet (on the assumption that when I get a couple more drives, I would add a second Data drive and then the Parity drive).

 

However, when I allocate the only drive as Data Disk 1, and click Start, the web page shows that the drive is "mounting"I assume it is formatting the drive at this time).  This stays like this for maybe 10 minutes or more when I come back and refresh the page, and I can also hear disk activity.  But then if I come back a little later and refresh the page, I get no response (ie. the web server is not responding).

 

If I logon to the console as root, the server is still responding (ie. has not locked up), so I can shutdown successfully etc.

 

If I restart the system, I am back at square one!

 

Any ideas what I am doing wrong?  Or is it a problem caused by only having one drive attached?  Do I need to go and buy a couple more drives to get started (although I would prefer to test all is operating with one drive first - if possible).

 

TIA

 

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You might need to start with at least 2 drives, one being parity, the reason being I believe unraid need a baseline system to start with.  I'm not sure what post you're referring to about no parity drive but I know you don't need one if you have a built array and the drive fails.  You can then still mount your array and transfer data, it will just be unprotected.  Do you have any spare drives lying around, any size will do? 

 

Does the main page have the option to restore the array instead of starting it?  It would be right below START but you would need to check the box 'I'm sure I want to do this'

 

If so you could try that.  As for formating that is taken care of after you start the array and all the disks are mounted.  I think your endless mounting loop is because you only having one drive.  It's possible you don't have a correct setting in bios for your the drive and that is causing it as well.

 

 

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Based on the documentation I've read, I'd agree with eirkatcuse...the minimum configuration is two drives.

 

From the "device setup" webpage (http://www.lime-technology.com/wordpress/?page_id=31):

 

"An unRAID server disk array consists of a single parity disk and a number of data disks. The data disks are exclusively used to store user data, and the parity disk provides the redundancy necessary to recover from any singe disk failure."

 

and later...

 

"Unlike traditional RAID systems which stripe data across all the hard drives, an unRAID system stores files on individual data disks. Consequently, all file write operations will involve both the data disk the file is being written to, and the parity disk. For these reasons,

 

    the parity disk size must be as large or larger than any of the data disks,

 

and

 

    given a choice, the parity disk should be the fastest disk in your system."

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I'm not sure what post you're referring to about no parity drive...

 

There were a couple of references I found posted by limetech:

 

Definitely you should be able to max out the 100Mb/s ethernet.  How many disks do you have and what rate are you getting for parity-check?  If you don't mind rebuilding parity later, one thing you can try is to create an array without parity (just unassign it on the Devices page).  This will take the s/w parity gen out of the equation.

 

And more specifically:

 

Also I hope someone can anwer this question.  CAn I setup UnRaid starting only with a Parity Drive and one Data drive?  I wanted to start this way before upgrading to the 6 drive package.

Sure you can have just 1 data drive.  You could also have a JBOD by simply not assigning a parity disk.

 

So I think I might have another issue.  I setup the BIOS as AHCI, based on my initial testing experiences on this thread:

http://lime-technology.com/forum/index.php?topic=571.0

 

I think I will go back and set the ICH8R BIOS Southbridge back to 'IDE' mode for the SATA controller, and see if that makes any difference.

 

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I just did an experiment on my unRaid array.

 

I normally have a parity drive plus 7 data drives.  For this experiment I stopped the array, then I copied /boot/config/super.dat to a backup file.  (I made the backup copy of super.day so I would not have to wait through a full parity re-calculation when I restore all the drives later)

 

Next, I unassigned the parity drive and all of my data drives except for a single one. 

 

I then re-started the array.  It came up just fine with a single data drive and no parity drive.  I was still able to play an ISO image from that one data drive through its "Movies" user-share over the LAN on my laptop.

 

I stopped the array  (It is still considered an "array" when there is only one drive? ??? )

 

I copied my backup copy of super.dat to /boot/config/super.dat

 

I used the web-interface to re-assign all my drives to their prior slots in the array.  (I did not try shuffling data drives around, but I think I could have.  Most important is to put the parity drive back on the correct physical drive it used to be on)

 

I re-started the array.  It came up perfectly fine, all my disks were back where they were.)

 

So... It sure looks like you can have just one data drive, and no parity drive, and still use unRaid as a network storage device.

 

Joe L.

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Thanks for proving this Joe.L. :)

 

Just viewed the syslog, and I'm getting an 'import' loop, so I'll start another topic to seek help on this problem (since the question of this topic is now resolved).

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However, when I allocate the only drive as Data Disk 1, and click Start, the web page shows that the drive is "mounting"I assume it is formatting the drive at this time).  This stays like this for maybe 10 minutes or more when I come back and refresh the page, and I can also hear disk activity.  But then if I come back a little later and refresh the page, I get no response (ie. the web server is not responding).

 

If I logon to the console as root, the server is still responding (ie. has not locked up), so I can shutdown successfully etc.

I've not gone through a single disk format/startup, I have added manny to my initial 2 drive config.

 

When you initially add a disk it is first cleared (and this can take quite a while for a large disk.  During this time the web-interface is not responsive. (One of my complaints too, as the whole unraid array is not available during this time) After clearing a filesystem is created on the disk, then the disk is mounted)

 

10 minutes or more is not unusual for this clearing process. In fact, with your 500Gig drive it could take an hour or more. 

 

I just did an experiment... I tried to read all of one of my 500Gig drives and send its contents to /dev/null.  it has been going for an hour now and only half of the disk has been read.  The total time to read it will probably be two hours. I think writing would take at least that time.  now, you have SATA drives and they may be faster than my IDE drives... but odds are VERY high that 10 minutes is way too short a time to clear your 500Gig drive.  Odds are you did not wait for the process to finish before deciding to reboot the unRaid server. 

 

If you see disk-activity lights you are probably observing the clearing process.  If the unraid server has really locked up you will see NO disk activity and no response from the web-interface and odds are you will not be able to log into the server using the console.

 

If you are seeing your disk in the dropdown list for assignment then odds are your motherboard settings are OK.  Setting the BIOS for IDE emulation may kill your PATA performance.

 

Try again, but be patient if the disk activity lights are blinking...

 

Joe L.

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When you initially add a disk it is first cleared (and this can take quite a while for a large disk.  During this time the web-interface is not responsive. (One of my complaints too, as the whole unraid array is not available during this time) After clearing a filesystem is created on the disk, then the disk is mounted)

 

Thanks Joe.

 

Although, based on the syslogs I posted in the my new 'import' - 'no device' post thread, the unraid appears to be in a loop trying to 'import' (whatever that means) the drive every minute?

 

I'm assuming from this, that the drive hasn't actually started clearing yet?

 

I can hear some disk activity, but the HDD light is not constantly on - in a way you would probably expect during a constant write 'clearing'.

 

PS: New topic thread on current issue is here:

http://lime-technology.com/forum/index.php?topic=597.0

 

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Hello!

 

Guys, I'm wondering is there any way to use unRAID with only one HDD? The problem is that my mini-pc is designed to install only one hard drive... :-(

 

Thank you!

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3 hours ago, The_Immortal said:

Guys, I'm wondering is there any way to use unRAID with only one HDD?

Yes, you can have only one device, it needs to be assigned as a data device.

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On 4/11/2019 at 1:35 AM, johnnie.black said:

Yes, you can have only one device, it needs to be assigned as a data device.

When you add a 2nd data disk to the system, I assume that the contents of the first drive are not lost (referencing the comment about unraid not being a traditional array). Is that correct?

 

Thanks in advance.

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59 minutes ago, MarkRMonaco said:

When you add a 2nd data disk to the system, I assume that the contents of the first drive are not lost (referencing the comment about unraid not being a traditional array). Is that correct?

 

Thanks in advance.

Correct. Each data disk is a separate file system. No striping.

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