Re: SS4000E Fan speed, LEDS and power button
Chris,
On Thu, Jul 19, 2012 at 09:49:53AM -0400, Chris Wilkinson wrote:
> Sorry for all the questions.
Well, it's what mailing lists are for :-)
> Should I create a swap partition on one disk prior to assembling
> RAID [...]
It depends on what you want.
If you want your swap on RAID, then no : you'll make the swap on the
assembled RAID set, like for other RAID sets.
But if you don't want RAID for swap, then you can create a swap
partition on any disk in the nas, even one on each disk if you want
(tough it's not usefull : you simply don't need (big) swap).
I take the swap on RAID approach because the disks where all the same
size (and so must be the RAID slices) and it was simpler.
> [...] , does it matter which disk it's on?
It also depends...
In the swap on RAID school, you will have a slice of each disk used by
the swap RAID set.
(Optimization ninjas will probably say here that the place of swap on
the disk itself matters, which is true in theory, but in practice, and
considering the low speed and/or usage of the box, these
considerations have little interest, if any...)
If the swap is apart, in theory it probably matters, but in practice I
think it will not make any difference where swap is. It's even
possible that the kernel will not use the swap at all. (Mine doesn't
swap a lot at all, if it does...)
> You said to make all to make all RAID slices the same size, [...]
(Yes, but obviously, all the same size **in a given RAID set**. You
can of course have RAID sets of different sizes, which is the case in
the output from yesterday.)
> [...] so the swap size would have to be allocated to a partition on
> all disks?
Yes, it's one of the possibilies. You'll probably find usefull
informations on RAID in the Debian installation manual if not already
read.
To summarize, take a look at this table :
lothar:~# sfdisk -l /dev/sd[a-d]
Disk /dev/sda: 38913 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting
from 0
Device Boot Start End #cyls #blocks Id System
/dev/sda1 0+ 303 304- 2441848+ fd Linux raid autodetect
/dev/sda2 304 365 62 498015 fd Linux raid autodetect
/dev/sda3 366 38912 38547 309628777+ fd Linux raid autodetect
Disk /dev/sdb: 38913 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting
from 0
Device Boot Start End #cyls #blocks Id System
/dev/sdb1 0+ 303 304- 2441848+ fd Linux raid autodetect
/dev/sdb2 304 365 62 498015 fd Linux raid autodetect
/dev/sdb3 366 38912 38547 309628777+ fd Linux raid autodetect
Disk /dev/sdc: 38913 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting
from 0
Device Boot Start End #cyls #blocks Id System
/dev/sdc1 0+ 303 304- 2441848+ fd Linux raid autodetect
/dev/sdc2 304 365 62 498015 fd Linux raid autodetect
/dev/sdc3 366 38912 38547 309628777+ fd Linux raid autodetect
Disk /dev/sdd: 38913 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting
from 0
Device Boot Start End #cyls #blocks Id System
/dev/sdd1 0+ 303 304- 2441848+ fd Linux raid autodetect
/dev/sdd2 304 365 62 498015 fd Linux raid autodetect
/dev/sdd3 366 38912 38547 309628777+ fd Linux raid autodetect
You see 4 disks of 320 GB each.
They are partionned exactly the same.
Next, I take each three groups of four same partitions on each disk to
assemble the RAID sets :
/dev/sd[a-d]1 make together /dev/md0 in RAID 1, mounted on /
/dev/sd[a-d]2 make together /dev/md1 in RAID1, formated as swap
/dev/sd[a-d]3 make together /dev/md2, in RAID5 mounted as /srv
> Where does the boot sector go? Does that need a partition?
I don't think so. Theses boxes are curiosa which doesn't boot from
hard disk, but from an embeded flash memory on the MB.
So, d-i will probably write the boot sectors on each disk of the RAID
set mounted as /, through the RAID device (/dev/md0 in my case), but
unusefully since the nas will not use hard disk to boot...
(I'm not absolulety sure, but I don't see either where the hard disks
are involved in the boot process...)
Hih,
--
JFS.
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