[
https://issues.apache.org/jira/browse/KAFKA-4844?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15899848#comment-15899848
]
Colin P. McCabe commented on KAFKA-4844:
----------------------------------------
http://nfs.sourceforge.net/#faq_d2
bq. D2. What is a "silly rename"? Why do these .nfsXXXXX files keep showing up?
bq. A. Unix applications often open a scratch file and then unlink it. They do
this so that the file is not visible in the file system name space to any other
applications, and so that the system will automatically clean up (delete) the
file when the application exits. This is known as "delete on last close", and
is a tradition among Unix applications. Because of the design of the NFS
protocol, there is no way for a file to be deleted from the name space but
still remain in use by an application. Thus NFS clients have to emulate this
using what already exists in the protocol. If an open file is unlinked, an NFS
client renames it to a special name that looks like ".nfsXXXXX". This "hides"
the file while it remains in use. This is known as a "silly rename." Note that
NFS servers have nothing to do with this behavior. After all applications on a
client have closed the silly-renamed file, the client automatically finishes
the unlink by deleting the file on the server. Generally this is effective, but
if the client crashes before the file is removed, it will leave the .nfsXXXXX
file. If you are sure that the applications using these files are no longer
running, it is safe to delete these files manually. The NFS version 4 protocol
is stateful, and could actually support delete-on-last-close. Unfortunately
there isn't an easy way to do this and remain backwards-compatible with version
2 and 3 accessors.
> kafka is holding open file descriptors
> --------------------------------------
>
> Key: KAFKA-4844
> URL: https://issues.apache.org/jira/browse/KAFKA-4844
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 0.9.0.1
> Reporter: chao
> Priority: Critical
>
> We found strange issue on Kafka 0.9.0.1 , kafka is holding opne file
> descriptors , and not allowing disk space to be reclaimed
> my question:
> 1. what does file (nfsXXXXX) mean ???
> 2. why kafka is holding file ??
> $ sudo lsof /nas/kafka_logs/kafka/Order-6/.nfs0000000004550ffc0000bd61
> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
> java 97465 kafka mem REG 0,25 10485760 72683516
> /nas/kafka_logs/kafka/Order-6/.nfs0000000004550ffc0000bd61
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
