zfs discuss - Jan 2010 - how do i prevent changing device names? is this even a problem in ZFS

I''m moving from FreeBSD to OpenSolaris in the next week or so (when the
rest
of my upgrade purchase arrives)

One thing i''m curious about is whether or not ZFS cares about changing
device names.

In FreeBSD I always used glabel to prevent this issue.  Does solaris have
something similar?  Is it even an issue (so many things in ZFS
aren''t...it''s
an amazingly robust solution)

please forgive my solaris ignorance.  I''ve been using FreeBSD for a few
years, and linux for a few years more but solaris is very new to me and
quite different in a lot of ways.
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On Sat, Jan 2, 2010 at 7:40 AM, Thomas Burgess <wonslung at gmail.com>
wrote:
> I''m moving from FreeBSD to OpenSolaris in the next week or so
(when the
> rest of my upgrade purchase arrives)
>
> One thing i''m curious about is whether or not ZFS cares about
changing
> device names.
>
> In FreeBSD I always used glabel to prevent this issue.  Does solaris have
> something similar?  Is it even an issue (so many things in ZFS
aren''t...it''s
> an amazingly robust solution)
>
> please forgive my solaris ignorance.  I''ve been using FreeBSD for
a few
> years, and linux for a few years more but solaris is very new to me and
> quite different in a lot of ways.
>
>
Nope, on import it will scan all the disks for ZFS pools.  It doesn''t
care
about the physical device names changing.


-- 
--Tim
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On Sat, 2 Jan 2010, Tim Cook wrote:
> 
> Nope, on import it will scan all the disks for ZFS pools.? It 
> doesn''t care about the physical device names changing.
It does seem to care after the pool has been imported.  A few people 
have been bit by hardware/BIOS/firmware updates which somehow changes 
the device names across reboots, or consumer hardware which changes 
IDs every time a removable device is plugged in. It is wise to export 
the pool before flashing new firmware which might cause a change to 
device IDs.  If you are using USB drives and plug the cables into 
different USB ports while the pool is still imported, then the pool 
will refuse to work.

FreeBSD seems to cause more issues due to changing device names than 
Solaris does.

Bob
--
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

On Sat, Jan 2, 2010 at 12:25 PM, Bob Friesenhahn <
bfriesen at simple.dallas.tx.us> wrote:
> On Sat, 2 Jan 2010, Tim Cook wrote:
>
>>
>> Nope, on import it will scan all the disks for ZFS pools.  It
doesn''t care
>> about the physical device names changing.
>>
>
> It does seem to care after the pool has been imported.  A few people have
> been bit by hardware/BIOS/firmware updates which somehow changes the device
> names across reboots, or consumer hardware which changes IDs every time a
> removable device is plugged in. It is wise to export the pool before
> flashing new firmware which might cause a change to device IDs.  If you are
> using USB drives and plug the cables into different USB ports while the
pool
> is still imported, then the pool will refuse to work.
>
> FreeBSD seems to cause more issues due to changing device names than
> Solaris does.
>
> Bob


well, i will be using the popular AOC-SAT2-MV8 cards (3 of them) with a
supermicro mbd-x7sbe motherboard.

I doubt i''ll even need the onboard controller at all seeing as i have
24
devices i plan to use (21 1tb drives and 3 ssd''s)

I just want to plan as well as i can.
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I''d recommend a SAS non-raid controller (with sas backplane) over sata.
It has better hot plug support.

I use the Supermicro SC836E1 and a AOC-USAS-L4i with a UIO M/b.

Mark.
-- 
This message posted from opensolaris.org

It''s too late.  I ordered 3 AOC-SAT2-MV8 cards.

when you say "better hot plug support" what exactly does that mean. 
It was
my understanding that the AOC-SAT2-MV8 was the same (or similar) controller
which sun used in the x4500

i know THAT has hotplug support (right?!?!)

the case i used has 20 hot swap bays which connect directly to the sata
controllers via normal sata cables (the norco 4020 case)
it''s not enterprise grade or anything but it''s pretty nice for
the money.
the backpane supports dual psu''s....i was also going to use a second
norco
case with a sas expander like this one

http://usa.chenbro.com/corporatesite/products_detail.php?sku=73

and a similar card like which you suggested for any additional storage....so
can you elaborate on "better hot plug support"


On Mon, Jan 4, 2010 at 5:05 AM, Mark Bennett <mark.bennett at
public.co.nz>wrote:
> I''d recommend a SAS non-raid controller (with sas backplane) over
sata.
> It has better hot plug support.
>
> I use the Supermicro SC836E1 and a AOC-USAS-L4i with a UIO M/b.
>
> Mark.
> --
> This message posted from opensolaris.org
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
>
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The earlier (2008) Opensolaris drivers tended to crash the server if you pulled
out an active drive. It may have improved in later releases.
In the case of the Sun Storage Appliances, the sata (and sas) drivers used are
different from those in Opensolaris and are considerably better featured.

My understanding is the chipset on the sata cards can''t handle drive
events as well as sas controllers do.

After testing of both options, I concluded that sas was the better choice
because of this, cabling complexity (24 bay chassis isn''t fun), and
expandability.
The controller and backplane price difference diminishes when you get to 24
bays.

Mark.
-- 
This message posted from opensolaris.org

so you''re saying that if i do something like fail a drive, then remove
it,
with my controller i''ll have a crash more than likely?

I can understand why sas might be better for some stuff but i thought sata
was supposed to support hot swap as well.....especially with the controller
i chose...

Don''t people use opensolaris on the x4500 as well?  bah...i guess
i''ll have
to wait and see....the stuff has already been paid for and will be here
soon.


On Wed, Jan 6, 2010 at 3:37 AM, Mark Bennett <mark.bennett at
public.co.nz>wrote:
> The earlier (2008) Opensolaris drivers tended to crash the server if you
> pulled out an active drive. It may have improved in later releases.
> In the case of the Sun Storage Appliances, the sata (and sas) drivers used
> are different from those in Opensolaris and are considerably better
> featured.
>
> My understanding is the chipset on the sata cards can''t handle
drive events
> as well as sas controllers do.
>
> After testing of both options, I concluded that sas was the better choice
> because of this, cabling complexity (24 bay chassis isn''t fun),
and
> expandability.
> The controller and backplane price difference diminishes when you get to 24
> bays.
>
> Mark.
> --
> This message posted from opensolaris.org
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
>
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