[mythtv-users] OT: SMB performance?

Pieter De Wit pieter at insync.za.net
Thu Jan 19 18:30:29 UTC 2012


On 20/01/2012 07:03, Matt Emmott wrote:
> Hey all,
>
> I recently completed a total overhaul of my home server 
> infrastructure. I found an insane deal on a Poweredge 2950 on eBay - 
> Dual 4-core Xeons, 8GB RAM, SAS RAID all for $300 - and set it up as 
> my new VMWare ESXi 5 server. It now holds all my VMs, including my 
> domain controller which serves DNS/DHCP/legacy WINS etc, my 
> PlayOn/Plex Media Server / Boxee Media Manager aggregator, my Win2008 
> file server, and my newly-virtualized MythBuntu master back end. 
> Storage is an Apple Xserve RAID fiber array, with two RAID-5 sets of 
> 2.7TB and 4TB.
>
> I also have a slave back end, currently using local disk for its 
> recordings storage, and an HDHomeRun PRIME for its three tuners. More 
> on that later.
>
> I have a 2TB LUN dedicated to my Windows server which holds all my DVD 
> and Blu-Ray rips. I consistently get between 85 and 95 MB/second SMB 
> transfer speeds between it and my windows machines throughout the 
> house over wired gigabit Ethernet. My original plan was to set up an 
> NFS mount on the Windows server and present at least another 2TB LUN, 
> dedicating that storage for MythTV recordings. I would then point my 
> MBE to that storage and move the HDHomeRun PRIME to that MBE. The 
> reasons for this are twofold: First, many of the technologies I want 
> to use including MythFuse, MythBoxee and XBMC's Mythbox app don't 
> support multiple master BEs - They expect all recordings to be in the 
> same place. Second, I like having everything centralized, and 
> front-ending it with a Windows server means that I can grow the 
> storage in the back end and have it be mostly transparent to the clients.
>
> Now, I'm a Windows Systems Admin by trade. I suck at all things Unix, 
> plain and simple. When going through the NFS setup and speaking with 
> friends who are smarter than me, they all suggested I just share 
> everything over SMB. However, I did some testing last night, and the 
> fastest transfers I can get to/from my Windows boxes and my two Myth 
> BEs is 30MB/second. All testing was done with a 14GB MKV. The Myth 
> servers are running XFS, and the Windows servers are NTFS with an 
> 8192k allocation unit size.  While this may be adequate for my needs, 
> I don't feel comfortable just accepting that I'm going to lose 60% of 
> my transfer speed potential. As I mentioned, my MBE is a vm (Please 
> don't hurt me), but my SBE is physical and both are displaying about 
> the same transfer rate. Neither of them are running the latest version 
> of Ubuntu... I believe they are both on 10.10.
>
> So, after this wall of text, my questions are: Is this slowness 
> expected due to the Linux implementation of SMB? Or is there something 
> horribly wrong with my setup? Should I attempt NFS again, or are there 
> ways to tune SMB to make it faster? Do newer versions of Ubuntu play 
> more nicely with SMB?
>
>
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Hi,

I would at least try a newer version. Since you have that shiny box 
there, firing up another VM won't be a problem. I am thinking 11.10, 
basic server install, mount smb, try.

Below is from a time long long ago and a land far far away...(more for 
history than anything else)
I do however recall a "bug" in Samba...I can't recall the exact details 
and this will hurt any Windows Sys Admin (I myself have ticked off over 
10 years as one :) ) Samba is sending the replies back to quickly...I 
can't remember the exact details of the packets etc, but there was a 
config file option intro'ed to fix this. "2" was our magic number.
</>

While searching for the above.....I do seem to recall a lot of people 
complaining about Samba, as a server, only serving up 30meg/sec, might 
be tied to the above... Can you clear up which is the server you are 
copying the file from (Windows "with 2TB lun"-> Linux local disk) ?

The other "issue" might be local disks...I have noticed that my local 
disk access has turned quite shocking...Adaptec SATA raid only giving me 
25-28 meg/sec....

A way around the above is the following:

d if=/mnt/smb/14gig.mkv of=/dev/null bs=4096

Increase the bs to higher and higher and see what works. If you would 
like to monitor the progress of the above command, run this

dd if=/mnt/smb/14gig.mkv bs=4096 | pv | dd of=/dev/null bs=4096

Replace /mnt/.... with the correct mount point.

If the list prefers, we can take this off list as it doesn't really 
cover myth, but rather Samba. Happy to post the outcome thou.

Cheers,

Pieter
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