[Gluster-users] libgfapi access

Pranith Kumar Karampuri pkarampu at redhat.com
Wed Dec 9 06:38:32 UTC 2015



On 12/08/2015 08:28 PM, Ankireddypalle Reddy wrote:
> Vijay,
>               We are trying to write data backed up by Commvault simpana to glusterfs volume.  The data being written is around 30 GB. Two kinds of write requests happen.
> 	1) 1MB requests
> 	2) Small write requests of size 128 bytes. In case of libgfapi access these are cached and a single 128KB write request is made where as in case of FUSE the 128 byte write request is handled to FUSE directly.
>
> 	glusterfs 3.6.5 built on Aug 24 2015 10:02:43
>
>                  Volume Name: dispersevol
> 	Type: Disperse
> 	Volume ID: c5d6ccf8-6fec-4912-ab2e-6a7701e4c4c0
> 	Status: Started
> 	Number of Bricks: 1 x (2 + 1) = 3
> 	Transport-type: tcp
> 	Bricks:
> 	Brick1: ssdtest:/mnt/ssdfs1/brick3
> 	Brick2: sanserver2:/data/brick3
> 	Brick3: santest2:/home/brick3
> 	Options Reconfigured:
> 	performance.cache-size: 512MB
> 	performance.write-behind-window-size: 8MB
> 	performance.io-thread-count: 32
> 	performance.flush-behind: on
hi,
      Things look okay. May be we can find something using profile info.

Could you post the results of the following operations:
1) gluster volume profile <volname> start
2) Run the fuse workload
3) gluster volume profile <volname> info > /path/to/file-1/to/send/us
4) Run the libgfapi workload
5)gluster volume profile <volname> info > /path/to/file-2/to/send/us

Send both these files to us to check what are the extra fops if any that 
are sent over network which may be causing the delay.

I see that you are using disperse volume. If you are going to use 
disperse volume for production usecases, I suggest you use 3.7.x 
preferably 3.7.3. We fixed a bug in releases from 3.7.4 till 3.7.6 which 
will be released in 3.7.7.

Pranith
>
> Thanks and Regards,
> Ram
>
>
> -----Original Message-----
> From: Vijay Bellur [mailto:vbellur at redhat.com]
> Sent: Monday, December 07, 2015 6:13 PM
> To: Ankireddypalle Reddy; gluster-users at gluster.org
> Subject: Re: [Gluster-users] libgfapi access
>
> On 12/07/2015 10:29 AM, Ankireddypalle Reddy wrote:
>> Hi,
>>
>>          I am trying to use  libgfapi  interface to access gluster
>> volume. What I noticed is that reads/writes to the gluster volume
>> through libgfapi interface are slower than FUSE.  I was expecting the
>> contrary. Are there any recommendations/settings suggested to be used
>> while using libgfapi interface.
>>
> Can you please provide more details about your tests? Providing information like I/O block size, file size, throughput would be helpful.
>
> Thanks,
> Vijay
>
>
>
>
>
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