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Posted to hdfs-user@hadoop.apache.org by ch huang <ju...@gmail.com> on 2013/12/12 02:07:47 UTC
how to corrupt a replica of a block by manually?
hi,maillist:
what is the sample way to corrupt a replica of a block ,i opened a
replica data file ,and delete a line,than use fsck ,nothing corrupt,
should the DN be restarted?
Re: how to corrupt a replica of a block by manually?
Posted by Adam Kawa <ka...@gmail.com>.
Hmmm.. I guess that you can try to read this file using
$ hadoop fs -cat <file-with-corrupt-replica> to detect that
When reading a file its checksums are calculated and compared to checksums
that were calculated during a write operation. If verification fails, NN is
notified about the corrupt replica and you will fetch a different replica
from another DN to read that file.
2013/12/12 ch huang <ju...@gmail.com>
> hi,maillist:
> what is the sample way to corrupt a replica of a block ,i opened a
> replica data file ,and delete a line,than use fsck ,nothing corrupt,
> should the DN be restarted?
>
Re: how to corrupt a replica of a block by manually?
Posted by Adam Kawa <ka...@gmail.com>.
Hmmm.. I guess that you can try to read this file using
$ hadoop fs -cat <file-with-corrupt-replica> to detect that
When reading a file its checksums are calculated and compared to checksums
that were calculated during a write operation. If verification fails, NN is
notified about the corrupt replica and you will fetch a different replica
from another DN to read that file.
2013/12/12 ch huang <ju...@gmail.com>
> hi,maillist:
> what is the sample way to corrupt a replica of a block ,i opened a
> replica data file ,and delete a line,than use fsck ,nothing corrupt,
> should the DN be restarted?
>
Re: how to corrupt a replica of a block by manually?
Posted by Adam Kawa <ka...@gmail.com>.
Hmmm.. I guess that you can try to read this file using
$ hadoop fs -cat <file-with-corrupt-replica> to detect that
When reading a file its checksums are calculated and compared to checksums
that were calculated during a write operation. If verification fails, NN is
notified about the corrupt replica and you will fetch a different replica
from another DN to read that file.
2013/12/12 ch huang <ju...@gmail.com>
> hi,maillist:
> what is the sample way to corrupt a replica of a block ,i opened a
> replica data file ,and delete a line,than use fsck ,nothing corrupt,
> should the DN be restarted?
>
Re: how to corrupt a replica of a block by manually?
Posted by Adam Kawa <ka...@gmail.com>.
Hmmm.. I guess that you can try to read this file using
$ hadoop fs -cat <file-with-corrupt-replica> to detect that
When reading a file its checksums are calculated and compared to checksums
that were calculated during a write operation. If verification fails, NN is
notified about the corrupt replica and you will fetch a different replica
from another DN to read that file.
2013/12/12 ch huang <ju...@gmail.com>
> hi,maillist:
> what is the sample way to corrupt a replica of a block ,i opened a
> replica data file ,and delete a line,than use fsck ,nothing corrupt,
> should the DN be restarted?
>