Plans for Logged/Journaled UFS

[Hussain Ali]

_______________________________________
From: owner-freebsd-fs at freebsd.org [owner-freebsd-fs at freebsd.org] On Behalf Of Thomas Burgess [wonslung at gmail.com]
Sent: Sunday, December 20, 2009 7:17 AM
To: Attila Nagy
Cc: freebsd-fs at freebsd.org
Subject: Re: Plans for Logged/Journaled UFS

i remember reading that NFS needs tuning with ZFS even on solaris so you
might want to look into that....i'm not an expert though.

I CAN say this though.  I have a machine with 12 drives and 8gb ram that i
use for samba.  FreeBSD 8.0 ZFS v13

It has only 10 or so clients but it has no problem maxing out 2 gigabit
lines and it never freezes.  It took some tuning for samba but it works
great.



On Sun, Dec 20, 2009 at 7:09 AM, Attila Nagy <bra at fsn.hu> wrote:

> For that problem, it can be true, the machine in speak has only 1 GB RAM
> (i386), although 8 disks.
> The freeze is a different beast, I've got it on 32-64 GB RAM machines (with
> NFS), and on 8 GB machines serving stuff with ftp/http/rsync/etc (no NFS).
> I'm not sure that the NFS and the non-NFS case is the same though.
>
> Thomas Burgess wrote:
>
>>
>> I think it depends on hardware and setup.  I've noticed the "zfs problem"
>> with SOME machines when it comes to rtorrent (the rtorrent process will be
>> stuck "waiting for disk" but on other machines it's fine.
>> The machines i've had the most problem with are single drive less than 2
>> gb ram.
>>
>> I've got rtorrent and zfs working fine on plenty of machines with 2-3 hard
>> drives and 4-8 gb ram.
>>
>> On Sun, Dec 20, 2009 at 6:51 AM, Attila Nagy <bra at fsn.hu <mailto:
>> bra at fsn.hu>> wrote:
>>
>>    Matthew Jacob wrote:
>>
>>        Hussain Ali wrote:
>>
>>
>>            ZFS doesnt suffice for may use cases - so just wondering
>>            if this is in
>>            the works.
>>
>>
>>        Which use cases can you name?
>>
>>    Reliable data storage. :(
>>
>>    Sadly, ZFS in FreeBSD is still very far from being stable. For
>>    example I have NFS servers running on ZFS, and they freeze about
>>    every week. It seems it's related to NFS.
>>    I can't even get to the debugger. After sending an NMI, the kernel
>>    writes "NMI ... going to debugger" eight times (those machines
>>    have 8 CPU cores) and nothing happens, I can only reset.
>>
>>    Another machine just looses ZFS access (all processes stuck in IO)
>>    on i386 if I run rtorrent with unlimited bandwidth with some
>>    torrents, or some disk intensive spam filtering. Access to UFS
>>    filesystems are still OK.
>>
>>    Also, running UFS and ZFS seems to have problems in 8-STABLE with
>>    UFS eating out memory from ZFS.
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>>
>>
>

ZFS is great for data warehousing and non high performance/high concurrent operations (Seen this on Solaris and FreeBSD).  I have about 350TB in FreeBSD's ZFS and its been running very stable but this is a data warehouse and I am not running off the shelf components either (HP DL 385's, Nexsan Satabeasts).  Ever use ZFS as a target for a replication for large and active MySQL DB, you would notice days worth of lag within a week (on same gear as the primay!). My cases maybe on the non typical average FreeBSD user usage, but for any large hosting environment I would assume its similar.

Anyway seems like we may see a journaled UFS in FreeBSD sometime soon. I hope the changes are minimal so its MFC'ed back into [78]-Stable.

http://jeffr-tech.livejournal.com/22716.html

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