differences between setup_harddisks and setup-storage

[Steffen Grunewald]

I had to upgrade a rather big cluster from Etch to Lenny this week.
The old fai server was still running fai_2.8.4sarge1, but the (Etch) 
nfsroot had fai-client_3.1.8 installed (Lenny: 3.2.17~lenny1).
Since the need to preserve several partitions always causes me headaches
I would have preferred to continue using setup_harddisks but somehow
the USE_SETUP_STORAGE setting slipped my attention.

I had to find that *even if I preserve_always* a certain partition at 
the "end" of the disk, setup-storage would complain about it (not ending
at a cylinder boundary: this is a RAID on a 3ware controller which would
fake geometries anyway) - I had to backup, drop the preserve_* setting,
and restore after installation.
Same happened to a 7TB partition (on an Areca controller) which had to be
created by hand previously (leaving the minimum of 34 sectors for GPT 
information at the beginning and end): I had to workaround this (by 
not declaring the disk at all in disk_config, and using my old manual
setup scripts to conditionally mkfs and add the fstab line).

In addition, I noticed that the new style would make partitions on "real
disks" (no geometry translation) _smaller_ than they were before, resulting
in a gap:

Disk /dev/sda: 164.6 GB, 164696555520 bytes
255 heads, 63 sectors/track, 20023 cylinders, total 321672960 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x39d139d0

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *          63     5237189     2618563+  83  Linux
/dev/sda2         5237190     7325639     1044225   82  Linux swap / Solaris
/dev/sda3         7325640     9414089     1044225   82  Linux swap / Solaris
/dev/sda4         9414090   321669494   156127702+   f  W95 Ext'd (LBA)
/dev/sda5         9414153    11502539     1044193+  83  Linux
/dev/sda6        11502603    13590989     1044193+  83  Linux
/dev/sda7        13591053    16723664     1566306   83  Linux
/dev/sda8        16820118   321669494   152424688+  83  Linux

(note the gap between sda7 and sda8 - about 96000 sectors!)

The corresponding disk_config partition sizes didn't change for years:

disk_config sda disklabel:msdos preserve_always:8 bootable:1
primary /               2560    ext3    rw,errors=remount-ro    createopts="-m1"
primary swap            1024    swap    rw
primary swap            1024    swap    rw
logical /tmp            1024    ext3    rw,nosuid               createopts="-m0"
logical /var            1024    ext3    rw                      createopts="-m1"
logical /opt            1536    ext3    rw                      createopts="-m1"
logical /scratch        1-      xfs     rw

Apparently the rounding strategy has changed... intentionally?

Cheers,
 Steffen

-- 
Steffen Grunewald * MPI Grav.Phys.(AEI) * Am Mühlenberg 1, D-14476 Potsdam
Cluster Admin * http://pandora.aei.mpg.de/merlin/ * http://www.aei.mpg.de/
* e-mail: steffen.grunewald(*)aei.mpg.de * +49-331-567-{fon:7233,fax:7298}
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