Re: Reading over than the file size on dispersed volume

[Jim Kinney <jim.kinney@xxxxxxxxx>]

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

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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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