zfs discuss - Apr 2007 - XServe Raid & Complex Storage Considerations

hello the list,

After reading the _excellent_ ZFS Best Practices Guide, I''ve seen in
the
section: ZFS and Complex Storage Consideration that we should configure 
the storage system to ignore command which will flush the memory into 
the disk.

So does some of you knows how to tell Xserve Raid to ignore
``fsync''''
requests ?

After the announce that zfs will be included in Tiger, I''ll be
surprised
that the Xserve Raid will not include such configuration.

Ced.

-- 

Cedric BRINER
Geneva - Switzerland

zfs-discuss-bounces at opensolaris.org wrote on 04/25/2007 10:17:50 AM:
> hello the list,
>
> After reading the _excellent_ ZFS Best Practices Guide, I''ve seen
in the
> section: ZFS and Complex Storage Consideration that we should configure
> the storage system to ignore command which will flush the memory into
> the disk.
>
> So does some of you knows how to tell Xserve Raid to ignore
``fsync''''
> requests ?
>
> After the announce that zfs will be included in Tiger, I''ll be
surprised
> that the Xserve Raid will not include such configuration.
<rant>
Xraid seems to be targeted towards pseudo cooperate customers -- the
controllers are independent and  do not allow for failover or mixed sets.
It would not surprise me if it is not tunable with regard to cache settings
(i have searched for these tunable myself). Apple seemed to just go
redundant enough (power supply, fans) to make the product appear at a
distance like it may fit into a reliable storage category  -- but once you
factor in losing half the storage to make it reliable it''s cost factor
is
doubled.  I hope that the next generation of this product line takes this
into account.
</rant>


-Wade

The Xraid is a very well thought of storage device with a heck of a price
point.  Attached is an image of the "Settings"/"Performance"
Screen where
you see "Allow Host Cache Flushing".

I think when you use ZFS, it would be best to uncheck that box.


The only 2 drawbacks to using Xserve raid that I have found are:

1. Partition Management, dynamic expansion and Volume management.  If we
stay native in OSX tools/filesystems we cant partition with free space then
later try to create a partition and retain the data from the already created
partition.  This really sucks.  I''m betting Xsan changes these
limitations
however.

2. Each controller can only talk to 7 disks (1/2 the array).


Other than that, the thing is really fast, and quite reliable.  Not to
mention the sexy blue lights that tell you its hummin''

-Andy

--

On 4/25/07 11:34 AM, "Wade.Stuart at fallon.com" <Wade.Stuart at
fallon.com>
wrote:
> 
> 
> 
> 
> 
> zfs-discuss-bounces at opensolaris.org wrote on 04/25/2007 10:17:50 AM:
> 
>> hello the list,
>> 
>> After reading the _excellent_ ZFS Best Practices Guide, I''ve
seen in the
>> section: ZFS and Complex Storage Consideration that we should configure
>> the storage system to ignore command which will flush the memory into
>> the disk.
>> 
>> So does some of you knows how to tell Xserve Raid to ignore
``fsync''''
>> requests ?
>> 
>> After the announce that zfs will be included in Tiger, I''ll be
surprised
>> that the Xserve Raid will not include such configuration.
> 
> <rant>
> Xraid seems to be targeted towards pseudo cooperate customers -- the
> controllers are independent and  do not allow for failover or mixed sets.
> It would not surprise me if it is not tunable with regard to cache settings
> (i have searched for these tunable myself). Apple seemed to just go
> redundant enough (power supply, fans) to make the product appear at a
> distance like it may fit into a reliable storage category  -- but once you
> factor in losing half the storage to make it reliable it''s cost
factor is
> doubled.  I hope that the next generation of this product line takes this
> into account.
> </rant>
> 
> 
> -Wade
> 
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
-- 


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On 25-Apr-07, at 12:17 PM, cedric briner wrote:
> hello the list,
>
> After reading the _excellent_ ZFS Best Practices Guide, I''ve seen
> in the section: ZFS and Complex Storage Consideration that we  
> should configure the storage system to ignore command which will  
> flush the memory into the disk.
>
> So does some of you knows how to tell Xserve Raid to ignore  
> ``fsync'''' requests ?
>
> After the announce that zfs will be included in Tiger,
Much as I would like to see it, I am not aware of any such  
announcement from Apple, only rumours.

--Toby
> I''ll be surprised that the Xserve Raid will not include such  
> configuration.
>
> Ced.
>
> -- 
>
> Cedric BRINER
> Geneva - Switzerland
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss

Toby Thain wrote:
>
> On 25-Apr-07, at 12:17 PM, cedric briner wrote:
>
>> hello the list,
>>
>> After reading the _excellent_ ZFS Best Practices Guide, I''ve
seen in
>> the section: ZFS and Complex Storage Consideration that we should 
>> configure the storage system to ignore command which will flush the 
>> memory into the disk.
>>
>> So does some of you knows how to tell Xserve Raid to ignore
``fsync''''
>> requests ?
>>
>> After the announce that zfs will be included in Tiger,
>
> Much as I would like to see it, I am not aware of any such 
> announcement from Apple, only rumours.
FWIW, I heard the rumor from their sales guys.

The wouldn''t say whether it ZFS would be available in 10.5 or 10.6, and
they wouldn''t say whether it ZFS-boot would be available when ZFS is 
introduced -- but they did confirm that it''s being worked on.

-Luke

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On Apr 25, 2007, at 10:54 AM, Andy Lubel wrote:
> The Xraid is a very well thought of storage device with a heck of a  
> price
> point.  Attached is an image of the
"Settings"/"Performance" Screen
> where
> you see "Allow Host Cache Flushing".
>
> I think when you use ZFS, it would be best to uncheck that box.
Yes, that''s the setting you''re looking for. The Xserve RAID
works
great with ZFS IME.

-- 
Ben


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They do need to start on the "next" filesystem and it seems very ideal
for Apple.  If they didn''t then apple will be making a huge mistake
because whatever FS''s exist now, zfs has already pretty much
trump''d it
on almost every level except for maturity.

I''m expecting ZFS and ISCSI(initiator and target) in Leopard.  After
all, OS X borrows from FreeBSD.. FreeBSD 7 has zfs ;)

Andy

-----Original Message-----
From: zfs-discuss-bounces at opensolaris.org
[mailto:zfs-discuss-bounces at opensolaris.org] On Behalf Of Luke Scharf
Sent: Wednesday, April 25, 2007 3:00 PM
To: Toby Thain
Cc: zfs at opensolaris
Subject: Re: [zfs-discuss] XServe Raid & Complex Storage Considerations

Toby Thain wrote:
>
> On 25-Apr-07, at 12:17 PM, cedric briner wrote:
>
>> hello the list,
>>
>> After reading the _excellent_ ZFS Best Practices Guide, I''ve
seen in
>> the section: ZFS and Complex Storage Consideration that we should 
>> configure the storage system to ignore command which will flush the 
>> memory into the disk.
>>
>> So does some of you knows how to tell Xserve Raid to ignore
``fsync''''
>> requests ?
>>
>> After the announce that zfs will be included in Tiger,
>
> Much as I would like to see it, I am not aware of any such 
> announcement from Apple, only rumours.
FWIW, I heard the rumor from their sales guys.

The wouldn''t say whether it ZFS would be available in 10.5 or 10.6, and
they wouldn''t say whether it ZFS-boot would be available when ZFS is
introduced -- but they did confirm that it''s being worked on.

-Luke

On Apr 25, 2007, at 11:17 AM, cedric briner wrote:
> hello the list,
>
> After reading the _excellent_ ZFS Best Practices Guide, I''ve seen
> in the section: ZFS and Complex Storage Consideration that we  
> should configure the storage system to ignore command which will  
> flush the memory into the disk.
>
> So does some of you knows how to tell Xserve Raid to ignore  
> ``fsync'''' requests ?
>
> After the announce that zfs will be included in Tiger, I''ll be  
> surprised that the Xserve Raid will not include such configuration.
You can tell the Xserve RAID to ignore cache flush commands, but the  
option to make this so is controller-wide and not settable on a per- 
LUN basis.

In the Xserve RAID management app, select a controller, click the  
Settings button and enter the admin password for the array. Then  
click the Performance tab, and make sure that the "Allow Host Cache  
Flushing" option is unchecked for the controllers you don''t want
that
on.

/dale

> The Xraid is a very well thought of storage device with a heck of a price
> point.  Attached is an image of the
"Settings"/"Performance" Screen where
> you see "Allow Host Cache Flushing".
> 
> I think when you use ZFS, it would be best to uncheck that box.
This is what happen when you do use GUI in your native language (french 
in my case). I finally understood what was the meaning in french, after 
reading it from your image in english :)

And your setting just boosted my BW from 0.8 MiB/s to 7 MiB/s * !!
good to see that it just works.
> The only 2 drawbacks to using Xserve raid that I have found are:
> 
> 1. Partition Management, dynamic expansion and Volume management.  If we
> stay native in OSX tools/filesystems we cant partition with free space then
> later try to create a partition and retain the data from the already
created
> partition.  This really sucks.  I''m betting Xsan changes these
limitations
> however.
I would love that the Xserve juste provide a way to exports 14 disks to 
the Host. In this way, we could manage it with zfs in a more fine 
grained fashion.
> 2. Each controller can only talk to 7 disks (1/2 the array).
> 
> Other than that, the thing is really fast, and quite reliable.  Not to
> mention the sexy blue lights that tell you its hummin''
yeah right.. quite sexy !
> 
> -Andy
Ced.
* (a MiB is a mebibyte 2^20 ref: http://en.wikipedia.org/wiki/Mebibyte)


-- 

Cedric BRINER
Geneva - Switzerland