pNFS: trouble test with fscache

pNFS: trouble test with fscache

[宫勐]

S:

I want to get benchmark from pNFS+ fscache with iozone

But  iozone can't work well
/proc/fs/nfsfs/volumes   show that  the fsc is YES

I have open cachefiled and mount a ssd (ext3/user_xattr) on /var/fscache

When I use iozone to test read/re-read   it can't write page to the SSD DISK

/var/log/messages  show that  first it can write 4 pages successfully

after NFS: nfs_getpages_from_fscache: no page: -105

Then it won't write any page to fscache

If i use( cp /mnt/file  ./ )    The fscache works well

I confuse and have google many web page.  change source code to latest
one  But can't handle it.
I wish any help


Thanks


                                yours

                                GongMeng

Re: pNFS: trouble test with fscache

[Bian Naimeng]

> S:
> 
> I want to get benchmark from pNFS+ fscache with iozone
> 
> But  iozone can't work well
> /proc/fs/nfsfs/volumes   show that  the fsc is YES
> 
> I have open cachefiled and mount a ssd (ext3/user_xattr) on /var/fscache
> 
> When I use iozone to test read/re-read   it can't write page to the SSD DISK
> 
> /var/log/messages  show that  first it can write 4 pages successfully
> 
> after NFS: nfs_getpages_from_fscache: no page: -105

  Please confirm whether do you have enough memory when get this error,
  i guess iozone eats lot of memory.

  And, maybe the information of /proc/fs/fscache/states is useful, please
  puts it.

-- 
Regards
Bian Naimeng

Re: pNFS: trouble test with fscache

[宫勐]

Thank you

I have checked the memory ( 12G.)  and  sometimes memory is only 512M
(I set it in grub.conf)

fscache works well  I have sent /proc/fs/fscache/states to David
(RedHat who write fscache)

ENOBUFS is just normal infor

But  once fscache detect a ENOBUFS  It can't alloc more buff   Then
no more data can be write to disk

nfs_readpages_to_fscache   __nfs_readpages_from_fscache may report ENOBUF

After that  no buff will be alloc

Thank you for replaying this mail

yours
GongMeng



On Wed, Sep 15, 2010 at 5:28 PM, Bian Naimeng <biannm@cn.fujitsu.com> wrote:
>> S:
>>
>> I want to get benchmark from pNFS+ fscache with iozone
>>
>> But  iozone can't work well
>> /proc/fs/nfsfs/volumes   show that  the fsc is YES
>>
>> I have open cachefiled and mount a ssd (ext3/user_xattr) on /var/fscache
>>
>> When I use iozone to test read/re-read   it can't write page to the SSD DISK
>>
>> /var/log/messages  show that  first it can write 4 pages successfully
>>
>> after NFS: nfs_getpages_from_fscache: no page: -105
>
>  Please confirm whether do you have enough memory when get this error,
>  i guess iozone eats lot of memory.
>
>  And, maybe the information of /proc/fs/fscache/states is useful, please
>  puts it.
>
> --
> Regards
> Bian Naimeng
>
>