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HDFS >> mail # user >> What if one of the directory(dfs.name.dir) rw error ?


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Re: What if one of the directory(dfs.name.dir) rw error ?
>>I dont know how to simulate a disk failure..

Couple of things you could do. chmod 000 is one.
1. umount -l
2. mount ro only
3. If machine has hot swappable disks, pull out a disk.

-Bharath

________________________________
From: ccxixicc <[EMAIL PROTECTED]>
To: hdfs-user <[EMAIL PROTECTED]>
Sent: Wednesday, May 25, 2011 1:07 AM
Subject: Re: What if one of the directory(dfs.name.dir) rw error ?
I'm using 0.20.2. 

I had some test. I dont know how to simulate a disk failure, just chmod 000 dir1, the namenode shutdown immediately. And NN will hang if the nfs server down.

 
 
------------------ Original ------------------
From:  "Harsh J"<[EMAIL PROTECTED]>;
Date:  Wed, May 25, 2011 03:49 PM
To:  "hdfs-user"<[EMAIL PROTECTED]>;
Subject:  Re: What if one of the directory(dfs.name.dir) rw error ?
 
Yes. But depending on the version you're using, you may have to
manually restart the NN after fixing the mount points, to get the
directories in action again.

2011/5/25 ccxixicc <[EMAIL PROTECTED]>:
>
> Hi,all
> I set dfs.name.dir to a comma-delimited list of directories, dir1 is in
> /dev/sdb1 dir2 is in /dev/sdb2 and dir3 is nfs derectory.
> What happens if /dev/sdb1 disk error, so dir1 cannot be read and write?
> What happens if nfs server down, so dir3 cannot be read and write?
> Will hadoop ignore the bad directory and use the good directory and continue
> server?
> Thanks.
>

--
Harsh J