17 Dec 2009 mones   » (Journeyer)

Migrating disk

I had in LJ the final story of the failed disk, so, having woken up in the mood of bloggin', it saves me a precious time :-). Lots of console output and boring stuff, you know, but here it goes:

The failing setup were two discs I synced manually from time to time, their partition table:

Disk /dev/sda: 200.0 GB, 200049647616 bytes
255 heads, 63 sectors/track, 24321 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0003b1cf

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         122      979933+  83  Linux
/dev/sda2             123         365     1951897+  82  Linux swap / Solaris
/dev/sda3             366        1581     9767520   83  Linux
/dev/sda4            1582       24321   182659050    5  Extended
/dev/sda5            1582        2189     4883728+  83  Linux
/dev/sda6            2190        2554     2931831   83  Linux
/dev/sda7            2555        2676      979933+  83  Linux
/dev/sda8            2677       24321   173863431   83  Linux

And mount points:
/dev/sda1               918322    445462    423864  52% /
/dev/sda3              9614148   5303228   3822544  59% /usr
/dev/sda5              4806904   3629392    933328  80% /var
/dev/sda6              2885780   1107812   1748652  39% /opt
/dev/sda7               918322      8256    861070   1% /tmp
/dev/sda8            171134396 135680768  35453628  80% /home

This setup, appart of the manual sync, had some issues to be addressed:

  • Because of packaging activities /var was always nearly full, so it had to be increased

  • Because of doubling the memory some months ago, there was less swap than current RAM size (2G), also something to fix

The hardware choice wasn't very difficult, as I tend to like Seagate, so balancing price, capacity and availability decided for a couple of ST3500418AS. These are SATA-II, while my motherboard is SATA-I only but aren't they supposed to be backwards compatible? Well, they are, but you have to setup a jumper to lower interface speed, otherwise the disc isn't even recognized by the motherboard.

Buying the discs had some more difficulties. First tried Alternate, but this time they pretend me to pay the SGAE[es] tax for media (which is around 12 euros per disc), despite I clearly explained these were system discs to be mounted in RAID (and the tax is supposed only to apply non-system drives). Phoned them even, but no way, so I finally rejected the discs and went Optize, which doesn't seem to have the supposedly legal problem Alternate has with declaring system discs. They were served on time and for less than 90 euros, so bravo for them :).

After having the bare metal, initially these options for migration were considered:

  • Buy a 2.5 disc, copy current data (a 250 Gb disc is enough), install the new system, copy back

  • Buy a hard disc enclosure for the remaining good disc, install the new system, use the enclosure to copy data back

  • Install new system in one disc (sda), copy data from current disc (sdb), replace old disc with second and setup RAID on a running system

But in the end I got it with a fourth option based on this later one: install a new system with all the RAID setup, disconnect second drive (like if the array had failed), reconnect and copy contents of old drive to new system, restore second RAID drive and add it again to the array, so it gets synced again. Nothing to buy and more fun to see how fast the MD rebuilds the array.

So finally this is the new partition table:
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000a9eb5

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         134     1076323+  fd  Linux raid autodetect
/dev/sda2             135         620     3903795   82  Linux swap / Solaris
/dev/sda3             621        2322    13671315   fd  Linux raid autodetect
/dev/sda4            2323       60801   469732567+   5  Extended
/dev/sda5            2323        3416     8787523+  fd  Linux raid autodetect
/dev/sda6            3417        3538      979933+  fd  Linux raid autodetect
/dev/sda7            3539       12170    69336508+  fd  Linux raid autodetect
/dev/sda8           12171       60801   390628476   fd  Linux raid autodetect

And mount points:
/dev/md0               1059264    263360    742096  27% /
/dev/md1              13456532   1703152  11069820  14% /usr
/dev/md2               8649480   1365644   6844464  17% /var
/dev/md3                964408     17632    897784   2% /tmp
/dev/md4              68248448    184216  68064232   1% /opt
/dev/md5             384497716 132355408 252142308  35% /home

BTW, after all I did buy the SATA enclosure for the remaining disc, so I have another 200Gb for pr0n ;-).

Syndicated 2009-10-29 06:24:51 from Ricardo Mones

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