[Samba] slow creating files

Al mailinglist at theflux.net
Thu Feb 16 18:38:29 MST 2012


Agreed, run 'top d1' then look at the line:

Cpu(s):  0.5%us,  0.5%sy,  0.0%ni, 99.0%id,  0.0%wa,  0.0%hi,   
0.0%si,  0.0%st

If you see '%wa' higher than 15.0 you have slow disk writing...

On Feb 16, 2012, at 12:36 AM, Pavel Plesov wrote:

> Hello,
> Have you checked the hardware ?
> Tools like dmesg, atop and iostat can be very helpful here.
> On Wed, Feb 8, 2012 at 17:10, Алексей Ганков  
> <a.v.gankov at gmail.com> wrote:
>> We tried to migrate from old Windows fileserver (p4, single HDD) to  
>> Samba
>> (FedoraCore15, Samba 3.5.12-72.fc15, ext4 volume, xeon, raid5).
>> Our pipeline is so, that some special software generates files on  
>> that
>> fileserver.
>> The typical filesize ~50 mbytes.
>> On the old hardware, software (win2k3 server) the time of single file
>> creation was about 10 seconds. On the new configuration it takes  
>> 20-25
>> seconds.
>> Copying of large files to\from samba server is ok (more than 80  
>> mbytes\sec).
>> It was default Samba installation.
>> The usual tuning doesn't help at all (TCPNODELAY etc...)
>>
>> Is there any idea for tuning?
>>
>> Also, I wrote easy test that confused me:
>>
>> #include "stdio.h"
>> #include "stdlib.h"
>> #include "time.h"
>> void main(int argc, char *argv[])
>> {
>> int fsize=40000000;
>> int i=0;
>> FILE *to;
>> char
>> str 
>> []= 
>> "0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890 
>> ";
>> time_t start, end;
>> double diff;
>>
>> time(&start);
>> to=fopen(argv[1], "w+");
>> for(i=0; i < fsize/100; i++)
>>    {
>>    fprintf(to, "\n%7d-%s",i, str);
>> /    fflush(to); // makes it slow!/
>>    }
>> fclose(to);
>> time(&end);
>> diff=difftime(end,start);
>> printf("\n \t time_diff =  %.2lf", diff);
>> }
>>
>> This was started on Win7 client PC, It creates about 40 mbytes size  
>> file in
>> pointed path.
>> Comparing timings on our samba share and win2k3 share gives: ~40  
>> seconds on
>> Samba and on  3-4 seconds win2k3!
>> That means that fflush cause dramatically slow down of fileshare.
>>
>> Alexey
>> --
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>
>
>
> -- 
> Pavel Plesov
> -- 
> To unsubscribe from this list go to the following URL and read the
> instructions:  https://lists.samba.org/mailman/options/samba



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