On 07/09/2016 02:14 PM, Marcin Sura wrote:
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
I think that is a good test to explore - Ben wrote that for exactly this kind of
workload.
For a single system (i.e., performance a single NFS client or local file
system), you could also test using fs_mark.
Regards,
Ric
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