zfs discuss - Aug 2010 - (preview) Whitepaper - ZFS Pools Explained - feedback welcome

Hello list, 

while following this list for more then 1 year, I feel that this list was a
great way to get insights into ZFS. Thank you all for contributing.

Over the last month''s I was writing a little "whitepaper"
trying to consolidate the knowledge collected here. It has now reached a
"beta" state and I would like to share the result with you. I call it

  - Whitepaper: ZFS Pooling Explained 

it can be found here as a preview.

http://www.storageconcepts.de/uploads/media/StorageConcepts_Whitepaper_-_ZFS_Pooling_explained_-1e.pdf

Link here: http://www.storageconcepts.de/produkte/nexentastor/videolog/

Feedback, comments and corrections are greatly appreshiated.

Regards, 
Robert
-- 
This message posted from opensolaris.org

Although it''s bit much Nexenta oriented, command wise. It''s a
nice introduction. I did found one thing, page 28 about the zil.
There''s no zil device, the zil can be written to an optional slog
device. And the last line first paragraph, "If you can, use memory based
SSD devices". At least change memory into dram, flash is also memory.
Perhaps even better is "If you can, use a non volatile dram based
device."
-- 
This message posted from opensolaris.org

dtrace is DTrace

On 8/25/2010 3:27 PM, F. Wessels wrote:
> Although it''s bit much Nexenta oriented, command wise.
It''s a nice introduction. I did found one thing, page 28 about the zil.
There''s no zil device, the zil can be written to an optional slog
device. And the last line first paragraph, "If you can, use memory based
SSD devices". At least change memory into dram, flash is also memory.
Perhaps even better is "If you can, use a non volatile dram based
device."
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Thanks for the feedback, the idea of it is to give people new to ZFS a
understanding of the terms and mode of operations to avoid common problems (wide
stripe pools etc.). Also agreed that it is a little NexentaStor
"tweaked" :)

I think I have to rework the zil section anyhow because of
http://opensolaris.org/jive/thread.jspa?threadID=133294&tstart=0 - have to
do some experiments here - and I will also do a "dual command
strategy" showing nexentastor commands AND opensolaris commands when a
command is shown.

That''s for the good feedback.

Regards, 
Robert
-- 
This message posted from opensolaris.org

This paper is exactly what is needed -- giving an overview to a wide audience of
the ZFS fundamental components and benefits.

I found several grammar errors -- to be expected in a draft and I think at least
one technical error.

The paper seems to imply that multiple vdevs will induce striping across the
vdevs, ala RAIDx0.  Though I haven''t looked at the code, my
understanding is that records are contained to a single vdev.

The clarification that each vdev gives iops roughly equivalent to a single disk
is useful information not generally understood.  I was glad to see it there.

Overall, this is a terrific step forward for understanding ZFS and encouraging
its adoption.

Now if only SRSS would work under Nexenta...
-- 
This message posted from opensolaris.org

> This paper is exactly what is needed -- giving an
> overview to a wide audience of the ZFS fundamental
> components and benefits.
Thanks :)
> I found several grammar errors -- to be expected in a
> draft and I think at least one technical error.
Will be fixed :)
> The paper seems to imply that multiple vdevs will
> induce striping across the vdevs, ala RAIDx0.  Though
> I haven''t looked at the code, my understanding is
> that records are contained to a single vdev.
Well according to
"http://www.filibeto.org/~aduritz/truetrue/solaris10/zfs-uth_3_v1.1_losug.pdf"
and other sources zfs uses so called "dynamic striping" here all data
is cpread across all disks. This is also why the failure of a single vdev is
critical to pool availability.
 
Robert
-- 
This message posted from opensolaris.org

On Wed, Aug 25, 2010 at 10:57 PM, StorageConcepts
<presales at storageconcepts.de> wrote:
> Thanks for the feedback, the idea of it is to give people new to ZFS a
understanding of the terms and mode of operations to avoid common problems (wide
stripe pools etc.). Also agreed that it is a little NexentaStor
"tweaked" :)
>
> I think I have to rework the zil section anyhow because of
http://opensolaris.org/jive/thread.jspa?threadID=133294&tstart=0 - have to
do some experiments here - and I will also do a "dual command
strategy" showing nexentastor commands AND opensolaris commands when a
command is shown.
I haven''t finished reading it yet (okay, barely read through the
contents list), but would you be interested in the FreeBSD equivalents
for the commands, if they differ?

-- 
Freddie Cash
fjwcash at gmail.com