Re: [Dump-users] back up to a hard drive

[Helmut J. <jar...@ig...>]

On 11 Apr, Anthony Ewell wrote:
> Hi All,
> 
>     With the cost of a decent small server tape drive
> (vxa2 $1100.00, decent scsi card and cable $300.00, plus $80.00
> per tape), I am thinking of using removable hard SATA
> drives instead.
> 
>     CRU makes a hot swappable carrier:
> 
>         http://www.cruinc.com/htmldocs/products/SATAdp5plus.htm
> 
> that comes well recommended.
> 
> Question:
> 
>     1)  as long as the backup drive is unmounted, will Linux
> freak out when the drive gets jerked out of its carrier?
> 
>     2)  will Linux get annoyed at the new hard drive being
> inserted (mount /dev/hdb1)?  (It will have a new serial
> number, etc.)

I am using an IDE drive in a USB2 case. You can use SATA drives in such
a case also.
Hotswapping works just fine. (assuming hotplug is installed correctly)
I'd guess this should work with a SATA drive, as well, if
CONFIG_HOTPLUG_PCI is selected in the kernel configuration.
Note, however, I had lots of trouble even with non-swappable
SATA drives with Linux before 2.6.12-rc1 (mightbe my
motherboard)

>     3)  would it be faster to leave compression on or off
> when doing a dump? (I will have lots of room on the backup
> drive.)

dump supports 3 compression modes. Only  -y (lzop) gives
good speed, more than 10 Mb/sec depending on the CPU.
Furthermore, dump uses several threads, so on a SMP machine
it compresses in parallel - quite noticable!

> 
>     4)  any gotchas I am missing?  Will dump work properly with
> this scheme?

Yes.


-- 
Helmut Jarausch

Lehrstuhl fuer Numerische Mathematik
RWTH - Aachen University
D 52056 Aachen, Germany