[Gluster-users] Reading over than the file size on dispersed volume

[Jim Kinney]

On a disperse setup shouldn't the various nodes have different parts of
the files and thus the md5sums would be different?
On Fri, 2018-01-12 at 18:17 +0900, jungeun kim wrote:
> Hi All,
> 
> I'm using gluster as dispersed volume and I send to ask for very
> serious thing.
> I have 3 servers and there are 9 bricks.
> 
> My volume is like below.
> ------------------------------------------------------
> Volume Name: TEST_VOL
> Type: Disperse
> Volume ID: be52b68d-ae83-46e3-9527-0e536b867bcc
> Status: Started
> Snapshot Count: 0
> Number of Bricks: 1 x (6 + 3) = 9
> Transport-type: tcp
> Bricks:
> Brick1: server1:/data/brick1
> Brick2: server2:/data/brick1
> Brick3: server3:/data/brick1
> Brick4: server1:/data/brick2
> Brick5: server2:/data/brick2
> Brick6: server3:/data/brick2
> Brick7: server1:/data/brick3
> Brick8: server2:/data/brick3
> Brick9: server3:/data/brick3
> Options Reconfigured:
> network.ping-timeout: 10
> performance.write-behind: on
> features.quota-deem-statfs: on
> features.inode-quota: on
> features.quota: on
> transport.address-family: inet
> nfs.disable: on
> ------------------------------------------------------
> 
> I generated the temporary files by various size to test.
> But I have found out some files MD5 mismatch after uploading to
> glusterfs.
> 
> e.g
> fallocate -l 130352 test1 
> fallocate -l 2281569280 test2
> fallocate -l 667417616 test3 
> 
> I have to calculate to make MD5 after uploading. 
> But the total size is different when reading the files to EOF. and
> MD5 is different, too.
> ( I write 42byte header in each files when create the file )
> 
> 
>     char buf[128*1024] = {0,};
>     offset += 42;
>     while ((retr = glfs_pread(fd, (void*)&buf, sizeof(buf), offset,
> 0)) > 0) {
>         DEBUG("retr : %ld, offset : %ld(%d)", retr,offset,errno)    ;
>         offset += retr;
>         MD5_Update(&context, buf, retr);
>     }
> 
>     DEBUG("total : %d", offset);
> 
> [DEBUG] retr : 130394, offset : 42(0) (star_glusterfs.c:96)
> [DEBUG] retr : 1024, offset : 130436(0) (star_glusterfs.c:96)
> [DEBUG] retr : 636, offset : 131460(0) (star_glusterfs.c:96)
> [DEBUG] total : 132096 (star_glusterfs.c:109)
> 
> 
> Why the glfs_pread(or glfs_read) function reads until over than the
> file size ?
> 
> This is fine on dispersed (4+2) and (8+1) volume but it is happend on
> (6+3) or (6+4) or (7+2) disperse volume.
> I want to know exact cause.
> Thank you.
> 
> Regards,
> 
> Jenny
> 
> 
> 
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
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-- 
James P. Kinney III

Every time you stop a school, you will have to build a jail. What you
gain at one end you lose at the other. It's like feeding a dog on his
own tail. It won't fatten the dog.
- Speech 11/23/1900 Mark Twain

http://heretothereideas.blogspot.com/
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