On 01/02/2013 19:22, Phil Turmel wrote:

Hi Dominique,

[Top-posting repaired.  Please don't]

On 02/01/2013 01:19 PM, Dominique C. wrote:
[trim /]

quoted

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I was wondering what would be the best way to convert a 6 hdd raid 5 to
raid 6. Ideally without having to reformat everything and lose all the
data in the process. I have backups of the data but I don't look forward
reinstalling everything on that server.

1) Add a seventh drive to the system.

You can do this on the run if you have hotplug-capable sata ports or sas
ports.

2) Add that drive to the array w/ "mdadm --add"
3) Convert array to raid6 w/ "mdadm --grow --level=raid6"

You can do 2 & 3 on the run.

4) Monitor /proc/mdstat to see when it finishes.

Hi Phil,

Thanks for your answer, however I forgot to mention one thing: I used

6 hdd out of 6 possible. No possibility to expand at this stage....

quoted

The data only uses part of the space available.
Any other ideas ?

Shrinking is usually possible, but there are many more steps, depending
on what is in the array.

Please provide more detail.  The output of "lsdrv"[1] might be a good start.

Phil

[1] http://github.com/pturmel/lsdrv

Hi Phil,

Back from weekend, and still with my problem. Output of lsdrv is as follow:

PCI [ahci] 00:1f.2 SATA controller: Intel Corporation 6 Series/C200 
Series Chipset Family SATA AHCI Controller (rev 05)
├scsi 0:0:0:0 ATA      WDC WD30EZRX-00M {WD-WCAWZ1618149}
│└sda 2.73t [8:0] Partitioned (gpt)
│ ├sda1 95.37m [8:1] vfat {89EF-00F4}
│ │└Mounted as /dev/sda1 @ /boot/efi
│ ├sda2 29.80g [8:2] MD raid1 (0/6) (w/ sdd2,sde2,sdc2,sdb2,sdf2) 
in_sync 'solipym:0' {d2e6885b-2d25-6c5a-5f3d-e9a9a5daa736}
│ │└md0 29.80g [9:0] MD v1.2 raid1 (6) clean 
{d2e6885b:2d256c5a:5f3de9a9:a5daa736}
│ │                  swap {8e565dfc-c5fa-4c76-abe9-f3a5a6e8fcff}
│ ├sda3 186.26g [8:3] MD raid1 (0/6) (w/ sdf3,sdd3,sde3,sdc3,sdb3) 
in_sync 'solipym:1' {89d69c6f-2ea2-23f5-aec8-b67c403488ad}
│ │└md1 186.26g [9:1] MD v1.2 raid1 (6) clean 
{89d69c6f:2ea223f5:aec8b67c:403488ad}
│ │ │                 ext4 {ca4bff22-40d8-4b31-859e-bba063f01df1}
│ │ ├Mounted as 
/dev/disk/by-uuid/ca4bff22-40d8-4b31-859e-bba063f01df1 @ /
│ │ └Mounted as 
/dev/disk/by-uuid/ca4bff22-40d8-4b31-859e-bba063f01df1 @ 
/var/spool/hylafax/etc
│ └sda4 2.52t [8:4] MD raid5 (0/6) (w/ sdd4,sdb4,sde4,sdc4,sdf4) 
in_sync 'solipym:2' {84672b4c-8fae-7f38-bb4c-c911aa9d7444}
│  └md2 12.59t [9:2] MD v1.2 raid5 (6) clean, 512k Chunk 
{84672b4c:8fae7f38:bb4cc911:aa9d7444}
│   │                ext4 {a9cfe95c-1e62-4cf6-b2aa-65abbd0c77e4}
│   └Mounted as /dev/md2 @ /srv
├scsi 1:0:0:0 ATA      WDC WD30EZRX-00M {WD-WCAWZ1382990}
│└sdb 2.73t [8:16] Partitioned (gpt)
│ ├sdb1 95.37m [8:17] vfat {6EFD-1659}
│ ├sdb2 29.80g [8:18] MD raid1 (1/6) (w/ sda2,sdd2,sde2,sdc2,sdf2) 
in_sync 'solipym:0' {d2e6885b-2d25-6c5a-5f3d-e9a9a5daa736}
│ │└md0 29.80g [9:0] MD v1.2 raid1 (6) clean 
{d2e6885b:2d256c5a:5f3de9a9:a5daa736}
│ │                  swap {8e565dfc-c5fa-4c76-abe9-f3a5a6e8fcff}
│ ├sdb3 186.26g [8:19] MD raid1 (1/6) (w/ sdf3,sdd3,sde3,sda3,sdc3) 
in_sync 'solipym:1' {89d69c6f-2ea2-23f5-aec8-b67c403488ad}
│ │└md1 186.26g [9:1] MD v1.2 raid1 (6) clean 
{89d69c6f:2ea223f5:aec8b67c:403488ad}
│ │                   ext4 {ca4bff22-40d8-4b31-859e-bba063f01df1}
│ └sdb4 2.52t [8:20] MD raid5 (1/6) (w/ sdd4,sda4,sde4,sdc4,sdf4) 
in_sync 'solipym:2' {84672b4c-8fae-7f38-bb4c-c911aa9d7444}
│  └md2 12.59t [9:2] MD v1.2 raid5 (6) clean, 512k Chunk 
{84672b4c:8fae7f38:bb4cc911:aa9d7444}
│                    ext4 {a9cfe95c-1e62-4cf6-b2aa-65abbd0c77e4}
├scsi 2:0:0:0 ATA      WDC WD30EZRX-00M {WD-WCAWZ0995502}
│└sdc 2.73t [8:32] Partitioned (gpt)
│ ├sdc1 95.37m [8:33] vfat {16BF-AABE}
│ ├sdc2 29.80g [8:34] MD raid1 (2/6) (w/ sda2,sdd2,sde2,sdb2,sdf2) 
in_sync 'solipym:0' {d2e6885b-2d25-6c5a-5f3d-e9a9a5daa736}
│ │└md0 29.80g [9:0] MD v1.2 raid1 (6) clean 
{d2e6885b:2d256c5a:5f3de9a9:a5daa736}
│ │                  swap {8e565dfc-c5fa-4c76-abe9-f3a5a6e8fcff}
│ ├sdc3 186.26g [8:35] MD raid1 (2/6) (w/ sdf3,sdd3,sde3,sda3,sdb3) 
in_sync 'solipym:1' {89d69c6f-2ea2-23f5-aec8-b67c403488ad}
│ │└md1 186.26g [9:1] MD v1.2 raid1 (6) clean 
{89d69c6f:2ea223f5:aec8b67c:403488ad}
│ │                   ext4 {ca4bff22-40d8-4b31-859e-bba063f01df1}
│ └sdc4 2.52t [8:36] MD raid5 (2/6) (w/ sdd4,sda4,sdb4,sde4,sdf4) 
in_sync 'solipym:2' {84672b4c-8fae-7f38-bb4c-c911aa9d7444}
│  └md2 12.59t [9:2] MD v1.2 raid5 (6) clean, 512k Chunk 
{84672b4c:8fae7f38:bb4cc911:aa9d7444}
│                    ext4 {a9cfe95c-1e62-4cf6-b2aa-65abbd0c77e4}
├scsi 3:0:0:0 ATA      WDC WD30EZRX-00M {WD-WCAWZ1118226}
│└sdd 2.73t [8:48] Partitioned (gpt)
│ ├sdd1 95.37m [8:49] vfat {978F-21B2}
│ ├sdd2 29.80g [8:50] MD raid1 (3/6) (w/ sda2,sde2,sdc2,sdb2,sdf2) 
in_sync 'solipym:0' {d2e6885b-2d25-6c5a-5f3d-e9a9a5daa736}
│ │└md0 29.80g [9:0] MD v1.2 raid1 (6) clean 
{d2e6885b:2d256c5a:5f3de9a9:a5daa736}
│ │                  swap {8e565dfc-c5fa-4c76-abe9-f3a5a6e8fcff}
│ ├sdd3 186.26g [8:51] MD raid1 (3/6) (w/ sdf3,sde3,sda3,sdc3,sdb3) 
in_sync 'solipym:1' {89d69c6f-2ea2-23f5-aec8-b67c403488ad}
│ │└md1 186.26g [9:1] MD v1.2 raid1 (6) clean 
{89d69c6f:2ea223f5:aec8b67c:403488ad}
│ │                   ext4 {ca4bff22-40d8-4b31-859e-bba063f01df1}
│ └sdd4 2.52t [8:52] MD raid5 (3/6) (w/ sda4,sdb4,sde4,sdc4,sdf4) 
in_sync 'solipym:2' {84672b4c-8fae-7f38-bb4c-c911aa9d7444}
│  └md2 12.59t [9:2] MD v1.2 raid5 (6) clean, 512k Chunk 
{84672b4c:8fae7f38:bb4cc911:aa9d7444}
│                    ext4 {a9cfe95c-1e62-4cf6-b2aa-65abbd0c77e4}
├scsi 4:0:0:0 ATA      WDC WD30EZRX-00M {WD-WCAWZ1649385}
│└sde 2.73t [8:64] Partitioned (gpt)
│ ├sde1 95.37m [8:65] vfat {8875-2D50}
│ ├sde2 29.80g [8:66] MD raid1 (4/6) (w/ sda2,sdd2,sdc2,sdb2,sdf2) 
in_sync 'solipym:0' {d2e6885b-2d25-6c5a-5f3d-e9a9a5daa736}
│ │└md0 29.80g [9:0] MD v1.2 raid1 (6) clean 
{d2e6885b:2d256c5a:5f3de9a9:a5daa736}
│ │                  swap {8e565dfc-c5fa-4c76-abe9-f3a5a6e8fcff}
│ ├sde3 186.26g [8:67] MD raid1 (4/6) (w/ sdf3,sdd3,sda3,sdc3,sdb3) 
in_sync 'solipym:1' {89d69c6f-2ea2-23f5-aec8-b67c403488ad}
│ │└md1 186.26g [9:1] MD v1.2 raid1 (6) clean 
{89d69c6f:2ea223f5:aec8b67c:403488ad}
│ │                   ext4 {ca4bff22-40d8-4b31-859e-bba063f01df1}
│ └sde4 2.52t [8:68] MD raid5 (4/6) (w/ sdd4,sda4,sdb4,sdc4,sdf4) 
in_sync 'solipym:2' {84672b4c-8fae-7f38-bb4c-c911aa9d7444}
│  └md2 12.59t [9:2] MD v1.2 raid5 (6) clean, 512k Chunk 
{84672b4c:8fae7f38:bb4cc911:aa9d7444}
│                    ext4 {a9cfe95c-1e62-4cf6-b2aa-65abbd0c77e4}
â””scsi 5:0:0:0 ATA      WDC WD30EZRX-00M {WD-WCAWZ1383151}
  â””sdf 2.73t [8:80] Partitioned (gpt)
   ├sdf1 95.37m [8:81] vfat {A89B-DC05}
   ├sdf2 29.80g [8:82] MD raid1 (5/6) (w/ sda2,sdd2,sde2,sdc2,sdb2) 
in_sync 'solipym:0' {d2e6885b-2d25-6c5a-5f3d-e9a9a5daa736}
   │└md0 29.80g [9:0] MD v1.2 raid1 (6) clean 
{d2e6885b:2d256c5a:5f3de9a9:a5daa736}
   │                  swap {8e565dfc-c5fa-4c76-abe9-f3a5a6e8fcff}
   ├sdf3 186.26g [8:83] MD raid1 (5/6) (w/ sdd3,sde3,sda3,sdc3,sdb3) 
in_sync 'solipym:1' {89d69c6f-2ea2-23f5-aec8-b67c403488ad}
   │└md1 186.26g [9:1] MD v1.2 raid1 (6) clean 
{89d69c6f:2ea223f5:aec8b67c:403488ad}
   │                   ext4 {ca4bff22-40d8-4b31-859e-bba063f01df1}
   â””sdf4 2.52t [8:84] MD raid5 (5/6) (w/ sdd4,sda4,sdb4,sde4,sdc4) 
in_sync 'solipym:2' {84672b4c-8fae-7f38-bb4c-c911aa9d7444}
    â””md2 12.59t [9:2] MD v1.2 raid5 (6) clean, 512k Chunk 
{84672b4c:8fae7f38:bb4cc911:aa9d7444}
                      ext4 {a9cfe95c-1e62-4cf6-b2aa-65abbd0c77e4}
USB [usb-storage] Bus 002 Device 004: ID 059f:1010 LaCie, Ltd Desktop 
Hard Drive {ST3500830A            9QG6RC54}
â””scsi 6:0:0:0 ST350083 0AS
  â””sdg 465.76g [8:96] Partitioned (dos)
   â””sdg1 465.76g [8:97] ext4 {4c2f6b92-829d-4e53-b553-c07e0f571e02}
    â””Mounted as /dev/sdg1 @ /mnt
Other Block Devices
├loop0 0.00k [7:0] Empty/Unknown
├loop1 0.00k [7:1] Empty/Unknown
├loop2 0.00k [7:2] Empty/Unknown
├loop3 0.00k [7:3] Empty/Unknown
├loop4 0.00k [7:4] Empty/Unknown
├loop5 0.00k [7:5] Empty/Unknown
├loop6 0.00k [7:6] Empty/Unknown
├loop7 0.00k [7:7] Empty/Unknown
├ram0 64.00m [1:0] Empty/Unknown
├ram1 64.00m [1:1] Empty/Unknown
├ram2 64.00m [1:2] Empty/Unknown
├ram3 64.00m [1:3] Empty/Unknown
├ram4 64.00m [1:4] Empty/Unknown
├ram5 64.00m [1:5] Empty/Unknown
├ram6 64.00m [1:6] Empty/Unknown
├ram7 64.00m [1:7] Empty/Unknown
├ram8 64.00m [1:8] Empty/Unknown
├ram9 64.00m [1:9] Empty/Unknown
├ram10 64.00m [1:10] Empty/Unknown
├ram11 64.00m [1:11] Empty/Unknown
├ram12 64.00m [1:12] Empty/Unknown
├ram13 64.00m [1:13] Empty/Unknown
├ram14 64.00m [1:14] Empty/Unknown
â””ram15 64.00m [1:15] Empty/Unknown

Raid 5 volume is md2 with 6 disk out of 6 in use. No spare.And no space 
to add another one...

Dominique