Re: HDFS open file limit
There is no open file limitation for HDFS. The 'Too many open file' limit is for OS file system. Increase *system-wide maximum number of open files, Per-User/Group/Process file descriptor limits.* On Mon, Jan 27, 2014 at 1:52 AM, Bertrand Dechoux decho...@gmail.comwrote: At least for each machine, there is the *ulimit *that need to be verified. Regards Bertrand Bertrand Dechoux On Sun, Jan 26, 2014 at 6:32 PM, John Lilley john.lil...@redpoint.netwrote: I have an application that wants to open a large set of files in HDFS simultaneously. Are there hard or practical limits to what can be opened at once by a single process? By the entire cluster in aggregate? Thanks John -- Regards, ...Sudhakara.st
Re: HDFS open file limit
Hi John, There is a concurrent connections limit on the DNs that's set to a default of 4k max parallel threaded connections for reading or writing blocks. This is also expandable via configuration but usually the default value suffices even for pretty large operations given the replicas help spread read load around. Beyond this you will mostly just run into configurable OS limitations. On Jan 26, 2014 11:03 PM, John Lilley john.lil...@redpoint.net wrote: I have an application that wants to open a large set of files in HDFS simultaneously. Are there hard or practical limits to what can be opened at once by a single process? By the entire cluster in aggregate? Thanks John
RE: HDFS open file limit
What exception would I expect to get if this limit was exceeded? john From: Harsh J [mailto:ha...@cloudera.com] Sent: Monday, January 27, 2014 8:12 AM To: user@hadoop.apache.org Subject: Re: HDFS open file limit Hi John, There is a concurrent connections limit on the DNs that's set to a default of 4k max parallel threaded connections for reading or writing blocks. This is also expandable via configuration but usually the default value suffices even for pretty large operations given the replicas help spread read load around. Beyond this you will mostly just run into configurable OS limitations. On Jan 26, 2014 11:03 PM, John Lilley john.lil...@redpoint.netmailto:john.lil...@redpoint.net wrote: I have an application that wants to open a large set of files in HDFS simultaneously. Are there hard or practical limits to what can be opened at once by a single process? By the entire cluster in aggregate? Thanks John
