Setting up an e-SATA RAID array

[costre]

Hello!

I just bought a MicroNet SR4 external e-SATA hard drive. It's an array of four separate 1TB drives.

Just curious if there's any one way to go about setting this drive up? I'd like to be able to use all 4 TB, no mirroring or fancy things like that.

This is my output of fdisk -l,

root@albin-desktop:/home/albin# fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0009b28f

Device Boot Start End Blocks Id System
/dev/sda1 * 1 14590 117194143+ 83 Linux
/dev/sda2 14591 60558 369237960 83 Linux
/dev/sda3 60559 60801 1951897+ 82 Linux swap / Solaris

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000698ba

Device Boot Start End Blocks Id System
/dev/sdb1 1 121601 976760001 83 Linux

Disk /dev/sdg: 2000.4 GB, 2000409772032 bytes
255 heads, 63 sectors/track, 243202 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0005c5cf

Device Boot Start End Blocks Id System
/dev/sdg1 1 243202 1953520033+ 83 Linux

Disk /dev/sdh: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xa4b57300

Device Boot Start End Blocks Id System
/dev/sdh1 1 121601 976760001 7 HPFS/NTFS

Disk /dev/sdi: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x30353434

Disk /dev/sdi doesn't contain a valid partition table

Disk /dev/sdj: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000e0ae6

Device Boot Start End Blocks Id System
/dev/sdj1 1 244 1959898+ fd Linux raid autodetect
/dev/sdj2 245 121601 974800102+ fd Linux raid autodetect

Disk /dev/sdk: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000ee0dc

Device Boot Start End Blocks Id System
/dev/sdk1 1 244 1959898+ fd Linux raid autodetect
/dev/sdk2 245 121601 974800102+ fd Linux raid autodetect

Disk /dev/sdl: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00008c3f

Device Boot Start End Blocks Id System
/dev/sdl1 1 244 1959898+ fd Linux raid autodetect
/dev/sdl2 245 121601 974800102+ fd Linux raid autodetect



The drive(s) in question would be sdi (SDI) through sdl (SDL). It says "Linux raid autodetect", which I assume is a good thing?

I can see the four "activity"-LED's on the front of the drive light up and flash one after the other during boot-up, as Linux starts it obviously recognizes all the four drives.

All drives show up in gparted.

sdi shows 932 GB of "unallocated" space
sdj shows 1.87 GB of swap (swapon) , and 930 GB of "unknown" FS
sdk shows 1.87 GB of swap (swapon) , and 930 GB of "unknown" FS
sdl shows 1.87 GB of swap (swapoff), and 930 GB of ext3 FS (seemingly "damaged", it's got that red sign with the exclamation mark)

I don't feel like diving in head first, any tips or suggestions are greatly appreciated, this is my first attempt ever at messing around with raid!

Thanks in advance!

[costre]

OK, I resolved the issue on my own.

First I slated the disks using gparted, creating only one big partition on each one.
Then I used MDADM to create the raid array, in my case the command was

mdadm --create --verbose /dev/md0 --level=0 --raid-devices=4 /dev/sdi1 /dev/sdj1 /dev/sdk1 /dev/sdl1

/dev/md0 is the destination of the raid array
level is the raid level to be used, in this case RAID0
raid-devices is the number of disks, in this case four (4)
/dev/sdi1 through /dev/sdl1 are the four disks to be used in the array



I chose ext3 for the file system (perhaps I'll reformat it to something a little more fancy, but for now it'll do)

mkfs.ext3 /dev/md0

Then simply mount it at the desired mount point (I chose /media since it's after all an external, sort-of portable, drive)

mount /dev/md0 /media/raid

I could now check the array using

df -vhT

which gave me

Filesystem Type Size Used Avail Use% Mounted on
/dev/md0 ext3 3.6T 197M 3.4T 1% /media/raid

That's it!

It's as simple as that. Hopefully it'll work after reboot etc

[psusi]

I hope you have a good backup plan you use frequently. With 4 disks the odds of a failure are 4 times more likely. If you loose one you loose all your data. You might want to go with a raid 5 instead so you can handle a single disk failure.

[costre]

I have considered that, but the disk stack is very well ventilated, and I don't have any irreplacables on it at all. Thanks for the tip, though

[costre]

Alright, I seem to have been more n00bish than I thought when it comes to raid.

The device I'm trying to configure is this:

http://store.micronet.com/SR44000E.aspx

The full name is a "4TB eSATA RAID with 2-port PCI-Express Card"

I hope this means it's hardware raid? The method I used in my previous post to arrange and mount the drives was (I learned) software raid.

So is it possible to configure hardware raid natively in Linux, or do you need special drivers? It says it supports XP, Vista, and OSX, but the customer support told me previous to the purchase that it worked in Linux.

I will mail the customer support, but any suggestions or comments on this issue from the Ubuntu community would be awesome

[Coreigh]

I did not find the explicit answer but I am guessing that this is software RAID all around. The PCIx card referenced is not specified as a RAID controller, although the description (website here) does say the product is "Bundled with an eSATA RAID controller,..." Is there software included with the device? When you boot the machine with the PCIx card installed is there a BIOS for the card that comes up after the machine BIOS before the OS? Hardware RAID settings would be there. If not then it is probably software RAID.

There is nothing *wrong* with software RAID, except that it is not hardware and is not as resilient. Keep back ups up to date and you will be fine.

Some of the reviews state that the RAID 5 included with the system is too slow. This may not be the case with Linux mdadm and you may have lesser performance needs than the reviewers.