zfs discuss - Dec 2008 - ZFS fragments 32 bits RAM? Problem?

I see this old post about ZFS fragmenting the RAM if it is 32 bit. This makes
the memory run out. Is it still true, or has it been fixed?

http://mail.opensolaris.org/pipermail/zfs-discuss/2006-July/003506.html
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This message posted from opensolaris.org

On Fri, Dec 05, 2008 at 11:35:27AM -0800, Orvar Korvar
wrote:
> I see this old post about ZFS fragmenting the RAM if it is 32 bit. This
makes the memory run out. Is it still true, or has it been fixed?
Don''t waste your time trying to run ZFS on a 32-bit machine.  The
performance
is horrible.  I really wish I hadn''t.

-brian
-- 
"Coding in C is like sending a 3 year old to do groceries. You gotta
tell them exactly what you want or you''ll end up with a cupboard full
of
pop tarts and pancake mix." -- IRC User (http://www.bash.org/?841435)

Its not me. There are people on Linux forums that wont to try out Solaris + ZFS
and this is a concern, for them. What should I tell them? That it is not fixed?
That they have reboot every week? Someone knows?
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This message posted from opensolaris.org

On 6-Dec-08, at 7:10 AM, Orvar Korvar wrote:
> Its not me. There are people on Linux forums that wont to try out  
> Solaris + ZFS and this is a concern, for them. What should I tell  
> them? That it is not fixed? That they have reboot every week?  
> Someone knows?

That it''s not recommended for 32 bit systems. There may also be  
unfixed atomicity issues in 64-bit operations, according to past  
posts on this list.

--Toby
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> This message posted from opensolaris.org
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> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss

On Sat, Dec 06, 2008 at 11:31:06AM -0500, Toby Thain
wrote:
> 
> > Its not me. There are people on Linux forums that wont to try out  
> > Solaris + ZFS and this is a concern, for them. What should I tell  
> > them? That it is not fixed? That they have reboot every week?  
> > Someone knows?
> 
> That it''s not recommended for 32 bit systems. There may also be  
> unfixed atomicity issues in 64-bit operations, according to past  
> posts on this list.
Well, he''s talking Linux, which means FUSE, so the issues related to
32-bit
on Solaris don''t apply as ZFS isn''t running in kernel space
which is where
the horrid performance issues come from (the ARC cache and the kernel fighting
for address space).  Maybe it would run well under 32-but Linux?  I
can''t
speak to that as I refuse to run Linux.

-brian
-- 
"Coding in C is like sending a 3 year old to do groceries. You gotta
tell them exactly what you want or you''ll end up with a cupboard full
of
pop tarts and pancake mix." -- IRC User (http://www.bash.org/?841435)

On Sat, Dec 06, 2008 at 12:42:44PM -0600, Tim wrote:
> "Solaris + ZFS and this is a concern"
> 
> Sounds to me like they want to try out solaris + zfs, not "zfs on
fuse".
Ooops, misread what he said.  Sorry about that.

I suppose my original comment still stands then. :)

-brian
-- 
"Coding in C is like sending a 3 year old to do groceries. You gotta
tell them exactly what you want or you''ll end up with a cupboard full
of
pop tarts and pancake mix." -- IRC User (http://www.bash.org/?841435)

On Sat, Dec 6, 2008 at 10:59 AM, Brian Hechinger <wonko at 4amlunch.net>
wrote:
> On Sat, Dec 06, 2008 at 11:31:06AM -0500, Toby Thain wrote:
> >
> > > Its not me. There are people on Linux forums that wont to try out
> > > Solaris + ZFS and this is a concern, for them. What should I tell
> > > them? That it is not fixed? That they have reboot every week?
> > > Someone knows?
> >
> > That it''s not recommended for 32 bit systems. There may also
be
> > unfixed atomicity issues in 64-bit operations, according to past
> > posts on this list.
>
> Well, he''s talking Linux, which means FUSE, so the issues related
to 32-bit
> on Solaris don''t apply as ZFS isn''t running in kernel
space which is where
> the horrid performance issues come from (the ARC cache and the kernel
> fighting
> for address space).  Maybe it would run well under 32-but Linux?  I
can''t
> speak to that as I refuse to run Linux.
>
> -brian
>
"Solaris + ZFS and this is a concern"

Sounds to me like they want to try out solaris + zfs, not "zfs on
fuse".

--Tim
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Does PAE help things at all on 32-bit ?



Brian Hechinger wrote:
> On Sat, Dec 06, 2008 at 12:42:44PM -0600, Tim wrote:
>   
>> "Solaris + ZFS and this is a concern"
>>
>> Sounds to me like they want to try out solaris + zfs, not "zfs on
fuse".
>>     
>
> Ooops, misread what he said.  Sorry about that.
>
> I suppose my original comment still stands then. :)
>
> -brian
>

On Sat, Dec 06, 2008 at 01:36:35PM -0800, Joseph Mocker
wrote:
> Does PAE help things at all on 32-bit ?
No.

-brian
-- 
"Coding in C is like sending a 3 year old to do groceries. You gotta
tell them exactly what you want or you''ll end up with a cupboard full
of
pop tarts and pancake mix." -- IRC User (http://www.bash.org/?841435)

Ok, thanx for your input, guys. So Bvians comment still is valid. I tell the
Linux guys that "OpenSolaris on 32 bit will fragment the memory to the
point that you have to reboot once in a while. It shouldnt corrupt your data
when it runs out of RAM."

Vodevick.
-- 
This message posted from opensolaris.org

>Ok, thanx for your input, guys. So Bvians comment still is valid. I
>tell the Linux guys that "Open Solaris on 32 bit will fragment the
>memory to the point that you have to reboot once in a while. It
>shouldnt corrupt your data when it runs out of RAM."

I''m not sure that that is completely true; I''ve run a small
32-bit file server
and it ran for half a year or more (except when I wanted to upgrade)

But that system had only 512 MB memory and I made the kernel''s VA
bigger
than the 512 MB, so it could map twice or three times that.

But it is a problem when you more memory then you can map (1GB will 
probably still work but 2GB is "too big".

I''ve now upgraded the system to an atom board (I don''t care
all that much
about its performance) but it does run 64 bit.

Casper

On Mon, Dec 8, 2008 at 4:39 AM,  <Casper.Dik at sun.com> wrote:
> I''m not sure that that is completely true; I''ve run a
small 32-bit file server
> and it ran for half a year or more (except when I wanted to upgrade)
>
> But that system had only 512 MB memory and I made the kernel''s VA
bigger
> than the 512 MB, so it could map twice or three times that.
>
> But it is a problem when you more memory then you can map (1GB will
> probably still work but 2GB is "too big".
        I have been running a small 32-bit server for over a year and
have not had any issues running out of memory.

Intel L-440GX+ server board with two P-iii 550 CPUs and 1 GB memory
2 x 500 GB PATA disks and 2 x 120 GB PATA disks in a ZPOOL (two vdev mirrors)
Solaris 10U4

        NFS performance is at least twice that of OpenSuSE 10.3 on the
same hardware to Mac OS X (10.4) clients.

........ although I am starting to shop around for replacement hardware.

-- 
{--------1---------2---------3---------4---------5---------6---------7---------}
Paul Kraus
-> Business Manager, Delta-Xi cast of Alpha-Psi-Omega @ RPI
-> Technical Advisor, RPI Players

On Mon, Dec 08, 2008 at 10:39:45AM +0100, Casper.Dik at Sun.COM
wrote:
> 
> >Ok, thanx for your input, guys. So Bvians comment still is valid. I
> >tell the Linux guys that "Open Solaris on 32 bit will fragment the
> >memory to the point that you have to reboot once in a while. It
> >shouldnt corrupt your data when it runs out of RAM."
I''ve not had that particular problem.  My RAM doesn''t get
fragmented, I''m just
very limited in the amount of memory that can be used by the ARC cache which has
a significant impact on my system''s performance.
> But that system had only 512 MB memory and I made the kernel''s VA
bigger
> than the 512 MB, so it could map twice or three times that.
> 
> But it is a problem when you more memory then you can map (1GB will 
> probably still work but 2GB is "too big".
This here is my problem.  I''ve got 4GB of RAM in the box. 
It''s.... painful. ;)
> I''ve now upgraded the system to an atom board (I don''t
care all that much
> about its performance) but it does run 64 bit.
I need to do something similar I believe.

-brian
-- 
"Coding in C is like sending a 3 year old to do groceries. You gotta
tell them exactly what you want or you''ll end up with a cupboard full
of
pop tarts and pancake mix." -- IRC User (http://www.bash.org/?841435)

>> But it is a problem when you more memory then you can map (1GB will 
>> probably still work but 2GB is "too big".
>
>This here is my problem.  I''ve got 4GB of RAM in the box. 
It''s.... painful. ;)
Have you changed kernelbase?  Lowering it will help performance.

Casper