Re: Debian 8.2 RAID conf. problem
On Wed, Oct 21, 2015 at 05:46:55PM +0100, Tony van der Hoff wrote:
> On 21/10/15 17:35, Mario Castelán Castro wrote:
> >El 21/10/15 a las 11:11, erdal daghan escribió:
> >>Hi,
> >>
> >>I have a problem with install debian. When I trying to install the Debian
> >>8.2 with RAID1 configuration it does NOT add bootable flag in guided
> >>partitioning mode. It Doesn't on option.
> >
> >The problem seems to be your perception, not Debian. Why do you think
> >you need that flag?. As far as I know, GRUB ignores it, so it makes no
> >difference regarding booting the system. Also, if you use guided
> >partitioning, you can manually adjust the suggested partitioning scheme
> >before proceeding, so if you really need it, you can easily toggle it.
> >
> >El 21/10/15 a las 11:11, erdal daghan escribió:
> >>Please help me.. I have two ssd disks(240gb). I want to make RAID1
> >>configuration.
> >
> >You probably refer to ordinary solid state drives which are NOT disks.
> >
>
> This raises a question in my mind: Should SSDs be used in RAID arrays?
As always, it depends on what you want to do.
RAID1 is done as a mechanism to give you a window between disk
failure and the need to replace the disk. Using identical SSDs
might not be a good strategy here, because identical write
patterns might produce identical failures.
I would consider something that keeps the secondary disk less
used than the primary - for instance, rsyncing primary to
secondary every so often. Once a day at minimum, once every 30
minutes or so max.
On the other hand, a database server might make good use of a
RAID10 of two kinds of similar but not identical disks - a disk
controller on a PCIe x8 slot can be saturated by 16 SATA3 SSDs
all running full-out.
Or you might want to use SSDs as caches for large spinning
disks. Generically, you can do this with bcache; if you use ZFS,
ZIL and L2ARC are what you are looking for.
-dsr-
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