[Samba] How Samba let us down

[James Hubbard]

I think everyone else has suggested that you upgrade to 2.2.6.  I too 
would recommend this.  The company where I work had a Win2K box whose 
print jobs would get dropped depending on how the printing was setup. 
Upgrading fixed the problem.  I sent an e-mail about it about a week 
ago.  If you've already got the drivers installed on the workstations 
you might want to go ahead and insert the following into the printer 
section.

use client driver=Yes

I believe that the mem=nopentium option is not necessary with the newer 
kernels.

As far as browsing goes, you probably do want to get WINS setup and make 
sure that DNS is configured correctly.  I noticed that some of the 
browsing slowness issues went away when I moved from 2.2.1a to 2.2.5.  I 
don't know what browsing looks like after the upgrade 2.2.6.  I only 
work via ssh, since I'm away at school.  I can't actually be there to 
know what it feels like.

Just my little bit of advice.

James Hubbard

Chris de Vidal wrote:
> Athlon MP 1.8GHz (mem=nopentium)
> 2GB ECC SDRAM
> Tyan S2460(I think?)
> Antec 450W PS
> Lots of cooling
> 5 IBM DeskStar 120GB drives with 8MB caches in RAID 5
> 3ware 7580(I think?) 8-port hardware RAID
> 3ware hot-swappable drive cages
> Intel e1000 Gigabit NIC, full duplex, 1000MBit,
> autonegotiation off
> 3com Gigabit switch, autonegotiation off
> RedHat 7.3
> Kernel 2.4.19 with ACL support
> ext3 with ACL support
> Samba 2.2.5 with ACL support installed from a
> recompiled SRPM from the samba.org FTP site.
> Winbind
> NO nfs daemon (I hear it's buggy w/ ACLs)
> 
> We have a variety of clients, from DOS and OS/2 to
> Windows (9x-2000) and Linux.  The server acts as a
> print spooling area (the actual queues are on an NT
> server) and scratch area for database programmers to
> manipulate their flat database files.  As far as I
> know, these files are not commonly accessed by more
> than one user at a time.
> 
> THE PROBLEM
> 
> For the past year, our heaviest-used Netware server
> has been under more and more stress.. filling up,
> running out of licenses, slowing down, etc. 
> Preliminary tests using Samba on a fast Linux box
> showed anywhere from 70% to 1000% speed improvements,
> depending on the task.  The decision was made to
> switch it to Linux; the whole company is migrating
> away from Netware and we (as a unit, not speaking for
> the company) don't want to be completely trapped into
> Windows if we can help it.
> 
> The new hardware arrived and more preliminary tests
> indicated all looked good.  We were set to switch last
> Saturday night.  We turned off logins to the Netware
> box, backed it up, restored it to the new Linux box,
> set permissions, then made sure the various computers
> in the building could log in.
> 
> Yesterday, our first day, was rough.  For most of the
> day we fought random slow browsing with no
> explanation.  Clients would appear to lock up for
> several seconds.  We found some misconfigurations in
> smb.conf but the problems reappeared.  No errors were
> seen in any machines' logs on debug level 2.  I
> trimmed the smb.conf to a minimal number of options
> and that seemed to help with the slowness.  Today,
> however, the problem reappeared a few times with no
> errors in the logs that we could see.
> 
> The printers were missing some of the records sent to
> them to print, something that had never happened with
> Netware.  Every time the missing records were
> different.  Occasionally, it would work right. 
> Oplocks (kernel, level I and II) were left to defaults
> (turned on).
> 
> THE OUTCOME
> 
> Sadly, tonight we are installing a Windows NT server. 
> Installing a brand new server is actually cheaper for
> us than the 8 or so hours of downtime to back up the
> server, install NT on it, and restore the data to it. 
> We don't want to revert to Netware because so many
> clients have been reconfigured to log on only to the
> domain (DOS, OS/2, etc.) and that would require many
> more hours reversing those changes.  Also, some files
> have been added since leaving Netware.  We also
> decided to proceed to use NT because is more proven in
> this capacity.
> 
> CONCLUSION
> 
> To be fair, the problems could be related to some
> misconfiguration.  I have pasted the smb.conf below.
> 
> I fear it might just be an oplock problem, but it is
> not clear what would result if more than one user
> happened to try to write to a file with them disabled.
>   Every advice we found said to leave them on to
> prevent corruption and to improve performance.  We ran
> out of time to test it, and feared what failure would
> bring.  Running this:
> grep -r -B5 -A5 oplock /var/log/samba/ | grep -B5 -A5
> error
> produced only 5 of these errors
> oplock_break: receive_smb error (Connection reset by
> peer)
> from the same DOS machine from 2 days worth of all
> machines' logs running at debuglevel 1 (some at level
> 2).  I don't know if that is a good indicator of an
> oplock problem.  I can do other greps on request.
> 
> Unfortunately, we can't test out your suggestions in
> production, and our off-production testing apparently
> can't stress it well enough.  So please just take this
> email as input - I'm not looking for answers here,
> though advice is appreciated.
> 
> The problem could also have been environment or
> hardware.  We should know soon, as we are going to
> reinstall the original Samba server with NT, and the
> problems should reappear if hardware or environment. 
> If we do find that to be true, I will certainly reveal
> our findings to this mailing list.
> 
> And perhaps the problem was with ACLs.  We couldn't
> turn them off in production to test that theory.
> 
> It is likely that we will try Samba in this capacity
> again in the future with a more mature version.
> 
> Thanks for listening,
> /dev/idal
> 
> 
> [global]
>         server string             =
>         workgroup                 = <our domain>
>         password server           = <our PDC>
>         security                  = domain
>         encrypt passwords         = yes
>         smb passwd file           =
> /etc/samba/smbpasswd
>         veto files                = /lost+found/
>         winbind uid               = 10000-20000
>         winbind gid               = 10000-20000
>         winbind separator         = +
>         create mask               = 660
>         force create mode         = 660
>         directory mask            = 0770
>         force directory mode      = 0770
>         log file                  =
> /var/log/samba/%m.log
>         debuglevel                = 2
> 
> [print]
>         path                      = /share/print
>         writeable                 = yes
> 
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