I'll second that question. Is there a way to get Gluster to see the
same cache benefit that direct filesystem or NFS enjoys?
Jeremy
On 4/2/2010 2:38 AM, Jon Swanson wrote:
> Yeah, obviously it's not actually writing to physical disks. I'm
> assuming that because it's a small file size (32GB), most of that is
> just hitting the filesystem cache.
>
> What i'm curious about is why Gluster is not seeing similar benefits
> from filesystem cache.
>
> It is getting /some/ benefit:
> [root at linuxdb1 tiobench-gluster.2]# tiotest -b 16384 -r 4096 -f 32 -t
> 16 -d .
> Tiotest results for 16 concurrent io threads:
> ,----------------------------------------------------------------------.
> | Item | Time | Rate | Usr CPU | Sys CPU |
> +-----------------------+----------+--------------+----------+---------+
> | Write 512 MBs | 16.7 s | 30.731 MB/s | 2.0 % | 33.5 % |
> | Random Write 1024 MBs | 38.9 s | 26.314 MB/s | 1.8 % | 32.5 % |
> | Read 512 MBs | 4.8 s | 107.145 MB/s | 4.0 % | 221.4 % |
> | Random Read 1024 MBs | 4.2 s | 241.220 MB/s | 11.6 % | 543.4 % |
>
> There's no way it's getting 241 MB/s over gigabit with Random Read.
> I'm sure there's a reason for this, just curious as to what it is.
>
> On 04/02/2010 04:29 PM, Marcus Bointon wrote:
>> On 2 Apr 2010, at 09:10, Jon Swanson wrote:
>>
>>> ,----------------------------------------------------------------------.
>>>
>>> | Item | Time | Rate | Usr CPU | Sys
>>> CPU |
>>> +-----------------------+----------+--------------+----------+---------+
>>>
>>> | Write 512 MBs | 35.7 s | 14.361 MB/s | 0.5 % | 833.8
>>> % |
>>> | Random Write 1024 MBs | 100.6 s | 10.182 MB/s | 0.4 % | 379.5
>>> % |
>>> | Read 512 MBs | 0.1 s | 4043.978 MB/s | 74.2 % |
>>> 5832.1 % |
>>> | Random Read 1024 MBs | 0.2 s | 4171.521 MB/s | 131.2 % |
>>> 6425.0 % |
>>> `----------------------------------------------------------------------'
>>>
>> Either these numbers or units are wrong or you have some outrageously
>> fast disks! 4Gbytes/sec?? You have multiple FusionIOs or something?
>>
>> Marcus
>
>
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