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

[jungeun kim]

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
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