xfs + 100TB+ storage + lots of small files + NFS

[Marcin Sura]

Hi,

Friend of mine asked me about evaluation of XFS for their purposes.
Currently I don't have physical access to their system, but here are the
info I've got so far:

SAN:
- physical storage is from FSC array, thin provisioned raid 6 volume,
- volumes are 100TB+ in size
- there are SSD disks in the array, which potentially can be used for
journal
- storage is connected to the host via 10GbE iSCSI

Host:
- They are using CentOS 6.5, with stock kernel 2.6.32-*
- System uses all default values, no optimization has beed done
- OS installed on SSD
- Don't know exact details of CPU, but I assume some recent multicore CPU
- Don't know amount of RAM installed, I assume 32GB+

NFS:
- they are exporting filesystem via NFS to 10-20 clients (services), some
VMs, some bare metal
- clients are connected via 1GbE or 10GbE links

Workload:
- they are storing tens or hundreds of millions of small files
- files are not in single directory
- files are undek 1K, usually 200 - 500 bytes
- I assume, that some NFS clients constantly write files
- some NFS clients initiates massive reads, millions of random files
- those reads are on demand, but during peak hours there can be many of
such requests

So far they were using Ext4, after some basic test they observed 40%
improvement in application counters. But I'm afraid that those tests were
done in environment not even close to the production (not so big size of
filesystem, not so much files).

I want to ask you what would be best mkfs.xfs settings for such setup.

I assume, that they should use inode64 mount option for such large
filesystem with that amount of files, but I'm a bit worried about
compatibility with NFS (default shipped with CentOS 6.5). I think inode32
is totally out of scope here.

Any other hints for setting this stuff up?
Probably some recent OS/kernel would also help a lot, right?

Also, do you know any benchmark which can be used to simulate such
workload? I've googled a lot, but there is quite short list of
multi-threaded, small files oriented benchmarks. To be honest, I've found
only https://github.com/bengland2/smallfile to be close to what I need. Any
other alternatives?

BR
Marcin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://oss.sgi.com/pipermail/xfs/attachments/20160709/162addd7/attachment.html>