[Gluster-users] Unify over AFR with pre-existing data

Wed Jul 23 06:55:46 UTC 2008

Hi - I wrote a script to set attributes on pre-existing data, but I have done very little testing with it so far. If you want to try it out it might save you some manual labor. After some more testing I was going to post it to the list and the wiki but it looks like you might be able to use it now... It works and it seems safe enough as it doesn't do anything but add gluster attributes to files which don't have any. Let me know if it works for you, and if anyone has any suggestions for improvement. 

Thanks, 
Chris 

#!/bin/bash 

DIR=$1 

if [ -z $DIR ] 
then 
echo 
echo "Error - no path was given." 
echo 
echo "USAGE: set-attrs /path/to/check" 
echo 
echo "Run set-attrs to check all files and directories in the" 
echo "given path for glusterfs attributes. Any files without" 
echo "a glusterfs version will be given a version attr of 2" 
echo "and a createtime attr equal to the files last modified time." 
echo 
echo "Output information is logged to syslog (usually /var/log/messages)" 
echo 
exit 0 
fi 

set_attrs() { 

get_ver="getfattr --absolute-names -n trusted.glusterfs.version" 
set_ver="setfattr -n trusted.glusterfs.version" 
set_ct="setfattr -n trusted.glusterfs.createtime" 

if test "`$get_ver $i 2>/dev/null | fgrep -c trusted.glusterfs.version=`" = "0" 
then 
mods=$((mods+1)) 
# comment out next line to turn off logging 
initlog -n set-attrs -s "Setting attrs on $i" 
CT=`stat -c %Y $i` 
$set_ct -v $CT $i 
$set_ver -v 2 $i 
fi 
} 

mods=0 
checks=0 

initlog -n watch-dir -s "Starting a set-attrs run on path: $DIR" 

for i in `find $DIR -print` 
do 
set_attrs $i 
checks=$((checks+1)) 
done 

initlog -n watch-dir -s "Completed. $checks checks and $mods mods in this run" 

exit 0 

----- Original Message ----- 
From: "baggio liu" <baggioss at gmail.com> 
To: "Keith Freedman" <freedman at freeformit.com>, gluster-users at gluster.org 
Sent: Wednesday, July 23, 2008 2:47:01 AM GMT -05:00 US/Canada Eastern 
Subject: Re: [Gluster-users] Unify over AFR with pre-existing data 

Hi , 
thanks for reply. And pls see my comment inline. And question is still pending. has any more grace way to fix this issue?? 

Regards 
Baggio 

2008/7/23 Keith Freedman < freedman at freeformit.com >: 

I had 2 situations with pre-existing data and I solved the both 2 different ways. 

1), I followed the instructions in the link provided, however, I was running xfs on the underlying filesystem and so the command to add attributes is different. 
in this case, it's attr instead of setfattr to set the extended attribute. Also, I *think* the actual attribute name is different. 

The extension attr names are hard-code , so it should not change according to underlying fs. 

so, what I recommend is to create one file through gluster, view it's extended attributes through the base filesystem then apply those to the remaining files. 

2) This is the less friendly but more surefire solution: 
make the gluster source point a sub directory in the source filesystem. 
then "move" the files into the gluster filesystem. 
This is less handy for "live" data, but it does insure the existing data is properly "glustered" 

This way can make data right, but too many extra cost has been involved. In our plan, hundreds of TB should be stored in this fs , This loop may cost several days . So it can not be tolerated. 

here's what I did: 
CURRENT SOURCE: /home 
GLUSTER SOURCE /home/home 
GLUSTER MOUNT POINT /gluster/home 

(this may not be syntatically correct): 
cd /home 
for i in * 
do 
if [ $i != 'glusterhome' ] 
mv $i glusterhome 
ln -s gluster/home/$i $i 
fi 

then unmount /gluster/home, unmount /home remount /home on /gluster 
now you have /gluster/home with your data which has the gluster attributes attached. 
mount glusterfs from /gluster/home to /home 

I actually used this second procedure to get the data onto my new AFR mirror. It slowed the process down since it was replicating 50GB of data while moving it form disk to disk, but I'm not sure it slowed it down much. 

it seems to really mostly just reduce disk thrashing and my copy was going at near network speed. 

BTW, I'm not very clear of it, Could you explain in detail? or list some example, test result, and so on. thx 

Keith 

At 07:11 PM 7/22/2008, baggio liu wrote: 

Hi guys, 
I have configured a cluster with unify over afr. one of server in afr has some pre-existing data. And I want to make these data can be seen by client. 
Some config have been done according to 
"Setting up AFR on two servers with pre-existing data" 

< http://gluster.org/docs/index.php/Setting_up_AFR_on_two_servers_with_pre-existing_data > http://gluster.org/docs/index.php/Setting_up_AFR_on_two_servers_with_pre-existing_data 

But namespace can not aware with those data. 
After afr completing, ls at client , pre-existing data can not be seen. cat them, Input/output error can be found. 

What should I fix them? Thank you for any help. 

Regards 
Baggio 
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