<Solved after a fashion>4 * 1.5 TB drives in raid 6

[gezza]

Hi to all knowledgeable people.
I am setting up a workstation as follows---
1 boot drive 80Gb.
a../40Gb
b..swap 16GB
c..user partition approx 30GB (dldata)
the system has 8GB ram
The 4 * 1.5TB drives are being set up as raid 6 with 2 partitions.
a../home
b../mnt/data 2.7TB
The problem I have is that the 2.7TB partition has not formatted after 2 +  hours.
is this reasonable OR am I asking to much of this system and PCLinuxos 2010.12?
Your thoughts will be greatfully received (whatever)
Gezza

[T6]

the swap is too big i think, in the worst case it should be 1.5 times bigger than your ram, that is 12 gbs, in a desktop 8 of swap is basically too much unless you do suspend to disk

about the 4 hard disks, how are you connecting them?

did you created the partition with pclinux?  did you said check for bad blocks?  if that is the case it is possible that it still has some time left to finish

about raid 6, why are you using it?  just for speed?

[gezza]

Hello T6,
You can probably ignore the text below. the problem is that you cannot have a partition greater than about 2TB. 2.5 TB requires a different partition table ( GUID and GPT)and I do not know if PCLinuxOS supports it.
***************
fdisk /dev/md1
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x41506c14.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: The size of this disk is 3.0 TB (2974392647680 bytes).
DOS partition table format can not be used on drives for volumes
larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID
partition table format (GPT).
***************************

Ant thoughts knowledgeable people?
I tried LVM but the first disk died and I lost the lot. I then played with raid and found dead disks were not such a problem.
Since that time, I have raided all my system except the laptops, and I feel much safer that way.
Since drives are not too expensive at this time, and being on an OZ pension, I decided to get the best deal I could on the drive front.
I have been told by my better half that I must now consolidate all dieing bits into other machines, until i have only one left. After that I am not sure what will happen!!
I am setting this machine up both W/S and local server.
Since the amount of space available that should work well?
The swap has been set at 2*ram so that I do not have to bother with hibernating, no matter what I am doing. Although I can certainly reduce swap if you think that would be better.
I do almost everything in PCLinuxos and have done so since 0.93.
Ii do not know if raid 6 is faster than 1 drive but it is certainly safer.
Gezza

[rubentje1991]

You want to partition it as Fat32 / ...? => DOS-like filesystem...


Why not use ext4?:

Large file system
    The ext4 filesystem can support volumes with sizes up to 1 exabyte and files with sizes up to 16 terabytes.[9] The current e2fsprogs can only handle a filesystem of 16 TB,[10] but support for larger filesystems is under development.

(http://en.wikipedia.org/wiki/Ext4)

I think you won't fill up that this evening 

[gezza]

Hi guy's
The DOS partition table is what we all use, It just means, as far as I have found out, the drive partition is too big.
It appears that 2TB is the largest partition you can have and it means you have to have a new boot/partition table
to hold the ?sectors that one needs.
Is PCLinuxOS going to support larger drives any time soon?
It appears that I can only use raid1 on these drives and have md0 and md1.
Gezza

[rubentje1991]

OK, maybe the problem lies there (I am not that kind of expert  )

[T6]

what type of partition are you trying to create?

afik there is no limit on the size of a ext4 partition presnt on any kernel

remember that you are using linux and linux kernel supports this

http://en.wikipedia.org/wiki/Ext4

"Limits
Max file size   16 TiB (for 4k block filesystem)
Max number of files   4 billion (specified at filesystem creation time)
Max filename length   256 bytes
Max volume size   1 EiB (limited to 16TiB because of e2fsprogs limitation)"

i believe that your raid 6 is the problem

i personally would work doing backups and not in raid 6, each hard drive alone or 4 in raid 1 but i am not a expert in raid arrays so can't recommend

[gezza]

Hi T6,
Many thanks for retuning.
Backing up 10GB of data takes a very long time.
That is why I went to raid.
So that with spare disks in the array losing one or two was not a real problem.
I wonder when we will support the bigger drives that are coming out, such as the 3TB drives.
I cannot the the purpose of ext4 supporting files sizes that are larger the the drives we currently have or likely to have in the near future.
Gezza

[T6]

the hard disks bigger than 2 tb supposedly are supported by linux natively afik

bigger sectors used by those drives are not problem for a linux, the problem is the bios accepting the bigger sizes, also xp can't work with it, only up to 2 tb and a driver forcing up to 2.5 if i understand correctly

what you are experiencing maybe could be problems with the raid itself, the hardware, maybe a new kernel could help but as i said i don't have enough experience to help or diagnose here

[gezza]

Hi to all,
What I need is to raid6 4*1.5TB drives, this gives me a partition of 2.5TB to format.
The format never finishes even after 5 hours. So a partition of this size is obviously not supported. Perhaps Tex could supply an answer.
I do not doubt that all the info given is correct, but if all is correct why cannot I format a raid6 partition of 2.5TB.
As I have said, I am booting on an 80GB drive with /(root) of 20GB a swap of 12GB and a download data partition of 42Gb.
On the raid6 system is /home(md0) and /mnt/data(md1).
I had hoped for /data to be 2.5TB but to get the system to work it is 1.3TB.
Again many thanks to all.
Gezza