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brando56894

Member

From: NYC

Registered: 2008-08-03

Posts: 681

Adding A New Drive To A Software RAID 5 Array

Edit 3: Just mounted the partitions and I can delete them because they contain nothing special. Is it safe to expand the 2nd partition of each drive to fill up the left over 22 GB?

Edit 2: I just deleted all the partitions off of my new drive and created one partition, then added it to the array and it works just fine. My next question is, can I delete all the smaller partitions and expand /dev/sd[x]2 to reclaim all the space (about 70 GB)?

One of my drives failed and Western Digital sent me a new drive, except it was an external drive instead of an internal drive, so I cracked it open and the label looked different. Turns out it's just refurbished and it's the same model as my other drives (WD Caviar Green 3 TB).

I've read through the wiki article on Software RAID and created the partitions exactly the same as my other drives, but while creating the main 2.7 TB partition it says that the ending sector is out of range when it isn't. I'm new to all this so I have no idea what to do. From what I've read there normally aren't this many partitions per disk, correct? I also have md124, md125 and md126 for the other partitions. md127 is for the 2.7 TB partitions. I took the array out of my Thecus N4520. I have a 3 TB external drive and a 1TB internal, along with another 500 GB drive. Would I be better off at destroying the RAID set and creating a fresh RAID 5 set, considering I'm losing about 90 GB if I don't need the smaller partitions.

/dev/sdc

Disk /dev/sdc: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 00636413-FB4D-408D-BC7F-EBAF880FBE6D
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 43941 sectors (21.5 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1        41945088        46139375   2.0 GiB     FD00  
   2        47187968      5860491263   2.7 TiB     FD00  THECUS
   3        46139392        47187951   512.0 MiB   FD00  
   4            2048        20973559   10.0 GiB    FD00  i686-THECUS
   5        20973568        41945071   10.0 GiB    FD00  

/dev/sdd

Disk /dev/sdd: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): C5900FF4-95A1-44BD-8A36-E1150E4FC458
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 43941 sectors (21.5 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1        41945088        46139375   2.0 GiB     FD00  
   2        47187968      5860491263   2.7 TiB     FD00  THECUS
   3        46139392        47187951   512.0 MiB   FD00  
   4            2048        20973559   10.0 GiB    FD00  i686-THECUS
   5        20973568        41945071   10.0 GiB    FD00  

/dev/sde

Disk /dev/sde: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 2B5527AC-9D53-4506-B31F-28736A0435BD
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 43941 sectors (21.5 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1        41945088        46139375   2.0 GiB     FD00  
   2        47187968      5860491263   2.7 TiB     FD00  THECUS
   3        46139392        47187951   512.0 MiB   FD00  
   4            2048        20973559   10.0 GiB    FD00  i686-THECUS
   5        20973568        41945071   10.0 GiB    FD00  

new drive: /dev/sdf

Disk /dev/sdf: 5860467633 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 93F9EF48-998D-4EF9-B5B7-936D4D3C7030
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860467599
Partitions will be aligned on 2048-sector boundaries
Total free space is 5813281700 sectors (2.7 TiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1        41945088        46139375   2.0 GiB     FD00  Linux RAID
   2        47187968        47187969   1024 bytes  FD00  Linux RAID
   3        46139392        47187951   512.0 MiB   FD00  Linux RAID
   4            2048        20973559   10.0 GiB    FD00  Linux RAID
   5        20973568        41945071   10.0 GiB    FD00  Linux RAID

when I type in 5860491263 as the end sector gdisk does nothing, just wants more input. If I type +2.7T it accepts it, but really it just creates a partition that's 1KB in size!

I am able to create a 2.7 TB partition with an end sector of 5860467599, this won't screw anything up will it?

Edit 1: just tried it and got this

 [root@ra /home/bran]# mdadm --add /dev/md127 /dev/sdf2
mdadm: /dev/sdf2 not large enough to join array
 [root@ra /home/bran]# fdisk -l /dev/sdf

Disk /dev/sdf: 2.7 TiB, 3000559428096 bytes, 5860467633 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 93F9EF48-998D-4EF9-B5B7-936D4D3C7030

Device           Start          End   Size Type
/dev/sdf1     41945088     46139375     2G Linux RAID
/dev/sdf2     47187968   5860467599   2.7T Linux RAID
/dev/sdf3     46139392     47187951   512M Linux RAID
/dev/sdf4         2048     20973559    10G Linux RAID
/dev/sdf5     20973568     41945071    10G Linux RAID

Last edited by brando56894 (2014-04-28 00:47:29)

Spider.007

Member

Registered: 2004-06-20

Posts: 1,176

Re: Adding A New Drive To A Software RAID 5 Array

Your edits make this post hard to read; but all your drives are 5860533168 sectors, and the new drive is 5860467633, which means the new drive is missing 65535 (~ 31M); so that explains the difficulties. That also means you'll never be able to replicate all partitions to this new drive; since all other drives leave only ~ 21M free. Unless you shrink one partition on all existing drives this will never work

Last edited by Spider.007 (2014-04-26 10:32:56)

brando56894

Member

From: NYC

Registered: 2008-08-03

Posts: 681

Re: Adding A New Drive To A Software RAID 5 Array

Sorry I numbered them to show the flow of information, this was also just a place for me to store info as I worked through it. I managed to get it to work by creating a partition that takes up the whole drive and is actually 22 GB larger than all the other drives (since I found out that the had root, swap and home partitions that are no longer needed).

I should be able to resize the other partitions without a problem, correct? They're EXT4. Should I unmount the raid array and do them individually, remount the array, let it sync and do the next? Or just unmount the array, resize all of them, mount it and let it sync?