I’ve seen CTDB + Samba deployed on several sites running Lustre. It’s stable in 
my experience, and straightforward to get installed and set up, although the 
process is time-consuming. The most significant hurdle is integrating with AD 
and maybe load balancing for the CTDB servers (RR DNS is the easiest and most 
common solution).

Performance is not nearly as good as for native Lustre client (apart from 
anything else, IIRC, SMB is a “chatty” protocol, esp with xattrs?). One 
downside of CTDB is that Lustre client must be mounted with -oflock in order 
for the recovery lock manager to work. Each individual connection to Samba from 
a Windows client is limited to the bandwidth and single thread performance of 
the CTDB node. Clients remain connected to a single CTDB node for the duration 
of their session, so there is a possibility of an imbalance in connections over 
time. Load balancing is strictly round-robin through DNS lookups, unless a more 
sophisticated load balancer is placed in front of the CTDB cluster.

There are references to CTDB + NFS / Ganesha as well but I haven’t had an 
opportunity to try it out. Most of the demand for non-native client access to 
Lustre involves Windows machines.

Malcolm.


From: lustre-discuss [mailto:lustre-discuss-boun...@lists.lustre.org] On Behalf 
Of Jeff Johnson
Sent: Wednesday, July 22, 2015 5:54 AM
To: Indivar Nair
Cc: lustre-discuss
Subject: Re: [lustre-discuss] [HPDD-discuss] Lustre Server Sizing

Indivar,

Since your CIFS or NFS gateways operate as Lustre clients there can be issues 
with running multiple NFS or CIFS gateway machines frontending the same Lustre 
filesystem. As Lustre clients there are no issues in terms of file locking but 
the NFS and CIFS caching and multi-client file access mechanics don't interface 
with Lustre's file locking mechanics. Perhaps that may have changed recently 
and a developer on the list may comment on developments there. So while you 
could provide client access through multiple NFS or CIFS gateway machines there 
would not be much in the way of file locking protection. There is a way to 
configure pCIFS with CTDB and get close to what you envision with Samba. I did 
that configuration once as a proof of concept (no valuable data). It is a 
*very* complex configuration and based on the state of software when I did it I 
wouldn't say it was a production grade environment.

As I said before, my understanding may be a year out of date and someone else 
could speak to the current state of things. Hopefully that would be a better 
story.

--Jeff



On Tue, Jul 21, 2015 at 10:26 AM, Indivar Nair 
<indivar.n...@techterra.in<mailto:indivar.n...@techterra.in>> wrote:
Hi Scott,

The 3 - SAN Storages with 240 disks each has its own 3 NAS Headers (NAS 
Appliances).
However, even with 240 10K RPM disk and RAID50, it is only providing around 1.2 
- 1.4GB/s per NAS Header.
There is no clustered file system, and each NAS Header has its own file-system.
It uses some custom mechanism to present the 3 file systems as single name 
space.
But the directories have to be manually spread across for load-balancing.
As you can guess, this doesn't work most of the time.
Many a times, most of the compute nodes access a single NAS Header, overloading 
it.

The customer wants *at least* 9GB/s throughput from a single file-system.

But I think, if we architect the Lustre Storage correctly, with these many 
disks, we should get at least 18GB/s throughput, if not more.

Regards,

Indivar Nair


On Tue, Jul 21, 2015 at 10:15 PM, Scott Nolin 
<scott.no...@ssec.wisc.edu<mailto:scott.no...@ssec.wisc.edu>> wrote:
An important question is what performance do they have now, and what do they 
expect if converting it to Lustre. Our more basically, what are they looking 
for in general in changing?

The performance requirements may help drive your OSS numbers for example, or 
interconnect, and all kinds of stuff.

Also I don't have a lot of experience with NFS/CIFS gateways, but that is 
perhaps it's own topic and may need some close attention.

Scott

On 7/21/2015 10:57 AM, Indivar Nair wrote:
Hi ...,

One of our customers has a 3 x 240 Disk SAN Storage Array and would like
to convert it to Lustre.

They have around 150 Workstations and around 200 Compute (Render) nodes.
The File Sizes they generally work with are -
1 to 1.5 million files (images) of 10-20MB in size.
And a few thousand files of 500-1000MB in size.

Almost 50% of the infra is on MS Windows or Apple MACs

I was thinking of the following configuration -
1 MDS
1 Failover MDS
3 OSS (failover to each other)
3 NFS+CIFS Gateway Servers
FDR Infiniband backend network (to connect the Gateways to Lustre)
Each Gateway Server will have 8 x 10GbE Frontend Network (connecting the
clients)

*Option A*
     10+10 Disk RAID60 Array with 64KB Chunk Size i.e. 1MB Stripe Width
     720 Disks / (10+10) = 36 Arrays.
     12 OSTs per OSS
     18 OSTs per OSS in case of Failover

*Option B*
     10+10+10+10 Disk RAID60 Array with 128KB Chunk Size i.e. 4MB Stripe
Width
     720 Disks / (10+10+10+10) = 18 Arrays
     6 OSTs per OSS
     9 OSTs per OSS in case of Failover
     4MB RPC and I/O

*Questions*
1. Would it be better to let Lustre do most of the striping / file
distribution (as in Option A) OR would it be better to let the RAID
Controllers do it (as in Option B)

2. Will Option B allow us to have lesser CPU/RAM than Option A?

Regards,


Indivar Nair



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Aeon Computing

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