LISTSERV mailing list manager LISTSERV 16.5

Help for XROOTD-L Archives


XROOTD-L Archives

XROOTD-L Archives


XROOTD-L@LISTSERV.SLAC.STANFORD.EDU


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Monospaced Font

LISTSERV Archives

LISTSERV Archives

XROOTD-L Home

XROOTD-L Home

XROOTD-L  August 2007

XROOTD-L August 2007

Subject:

Re: xrootd.prep

From:

Pavel Jakl <[log in to unmask]>

Date:

30 Aug 2007 10:08:57 -0400Thu, 30 Aug 2007 10:08:57 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (309 lines)

Hi Fabrizio and Roberto,


Fabrizio Furano wrote:
> Hi Pavel,
>
> thank you very much for the info. That is very useful for me. However
> I think that there is a version-based misunderstanding mixed to some
> bugs in the most recent ones. It looks like that in the old prod
> version there was no xrootd.prep directive, that's the point of
> confusion.
>
> In the meantime I reverted back to my local machine (and a simpler
> config file) to do this kind of tests. I believe I found a weirdness
> in the config error as reported. Here it is:
>
> - no xrootd.prep directive ---> prepare is off (ok!)
> - xrootd.prep logdir /tmp/prestage_log ---> the server refuses to start
Unfortunately, we don't use this directive, since we are not trying to
track prepare requests on the cluster.
If I do not specify directive in my version cvs checkout on 20070428, I
will just have a message 'xrootd.prepare logdir' not specified; prepare
tracking disabled.
This doesn't mean that prepare is disabled at all. You are just not
tracking requests.
>
> Step 1:
> Imho there is some bug in the config parsing, because having a look
> at the code and at the strace log, we see that xrootd creates the dir
> /tmp/prestage_log, and then looks for /tmp/prestage_log/anon, which
> was not created. Hence it exits with an error. This is very confusing.
> Andy, what do you think?
>
> 070830 14:22:40 001 XrootdConfig: Unable to process logdir
> /tmp/prestage_log; no such file or directory
> =====> xrootd.prep logdir /tmp/prestage_log
>
>
> Step 2:
> I create the dir /tmp/prestage_log/anon, and now the server starts,
> apparently fine.
Hum, there should be a MkDir somewhere, as you see anon is the default
instance name, if you do not specify none. So, there is a bug somewhere.
>
> Step 3:
> I connect with the xrd app and request a prepare. The server answers
> ok, and nothing happens... This is the request sent by the client:
>
>
> ================= DUMPING CLIENT REQUEST HEADER =================
> ClientHeader.streamid = 0x01 0x00
> ClientHeader.requestid = kXR_prepare (3021)
> ClientHeader.prepare.options = 0x08
> ClientHeader.prepare.prty = 0x00
> ClientHeader.prepare.reserved = 0 repeated 14 times
> ClientHeader.header.dlen = 5
> =================== END CLIENT HEADER DUMPING ===================
>
>
> And this is what the server says in the log (olbd says nothing):
>
> 070830 14:38:29 2295 furano.2318:[log in to unmask]
> XrootdProtocol: 0100 req=3021 dlen=5
> 070830 14:38:29 2295 furano.2318:[log in to unmask]
> XrootdResponse: 0100 sending 24 data bytes; status=0
> 070830 14:38:32 2295 furano.2318:[log in to unmask]
> XrootdProtocol: 0100 request timeout; read 0 of 24 bytes
> 070830 14:38:32 2295 furano.2318:[log in to unmask] XrdPoll:
> sending poller 0 enable for link 15
> 070830 14:38:32 2295 XrdPoll: Poller 0 enabled fd 15 entry 1 now at 2
> 070830 14:38:54 2295 XrdSched: running
> furano.2318:[log in to unmask] inq=0
> 070830 14:38:54 2295 XrootdXeq: furano.2318:[log in to unmask]
> disc 0:00:44
>
>
> Step 4:
> If I lurk inside /tmp/prestage_log/anon I see that the server created
> some files with complicated names, containing the filename I requested
> to stage. Now I am sure I am missing something, because still nothing
> happens. Instead the normal staging works. What's missing here? Andy,
> Pavel, do you have any suggestion? I attach my config file to the email.
Could you please paste which files are there ? If the prepare was
successful, then you should see a file request located in following file.

/tmp/pre_stage.queue.0.


The way how it should work is that xrootd on redirector node pass its
prepare request to olbd and olbd keeps track of servers which are able
to prepare files (you are saying it by olb.prep directive). When the
olbd on redirector node chooses best node to serve prepare request, the
request is passed trough the olbd to that server.
The chosen server will initiate add command on its forked olb prep
command and the particular prep command should add this file into its
queue. (this is the /tmp/pre_stage.queue.0)

Now it is a time to bring files from your tape system. So, the way how
it is done is that you need to run on each dataserver executable called
mps_PreStage. This executable needs to be started along with the xrootd
and olbd as a separate process. This executable is looking into this
/tmp/pres_stage.queue.0 and it is grabbing files one by one and
initiate this command in you configuration mps.pstg.pstgcmd.
Don't forget that you need to start mps_PreStage command with -c option
to pass the configuration file.

Could you please enable

olb.trace all debug
odc.trace all debug

in your configuration files ? So, we can see if the request is passed to
olb ?

Thanks
I hope I didn't confuse you
>
> Thank you!
> Fabrizio
>
>
>
>
>
>
>
> ------------------------------------------------------------------------
>
> #
> # $Id: xrootd.cf.example,v 1.2 2004/08/17 15:02:53 elmer Exp $
> #
> # The following is a sample xrootd configuration. The relevant prefixes are:
> #
> # acc - Access Control
> # odc - Open Distributed Cache
> # ofs - Open File System
> # oss - Open Storage System
> # sec - Security
> # xrd - Extended Request Daemon
> # xrootd - Xrootd Service
>
>
> #-----------------------------------------------
>
> # The Open Distributed Cache Section
> #
>
> # Tell xrootd who is the redirection manager
> #
> #odc.manager kanolb-a+ 3121
>
> #-----------------------------------------------
>
> # The Open File System Section
> #
>
> # Identify which machines will be redirecting clients
> #
> #ofs.redirect remote if kanolb-a+
>
> # Identify which machines clients will be redirected to (need not be inclusive)
> #
> #ofs.redirect target if kan0*
>
> #-----------------------------------------------
>
> # The Open Storage System Section
> #
>
> # Indicate where we hace mounted filesystems that can be used for space
> # The cache directive will also be used by the olb. So, we need not repeat it.
> #
> oss.cache public /tmp/cache*
>
> # While we highly recommend that you avoid path prefixing, here we indicate
> # the actual way files are physically name (i.e., the lfn to pfn mapping). The
> # localroot is how we name this on the data server while remoteroot tells the
> # system the corresponding name in the Mass Storage System.
> #
> oss.localroot /tmp/kanga
> oss.remoteroot /tmp/kanga_mss
>
> # Since we are using a Mass Storage System we need to indicate how MSS meta-data
> # information is retrieved (mssgwcmd) and how files are retrieved (stagecmd).
> # The xfr directive will limit the sumber of simultaneous stages to eight.
> #
> oss.mssgwcmd /home/furano/xrdtestmss/mymssgwcmd.pl
> oss.stagecmd /home/furano/xrootd/utils/mps_Stage -d -c /home/furano/xrdtestmss/xrootd.cf.fabrizio
> oss.xfr 8
>
> # Finally, we need to indicate, by path, which ones are migratable. This will
> # indicate which logical paths (i.e., lfn's) should exist in the MSS.
> #
> oss.path / nodread mig
>
> #-----------------------------------------------
>
> # The XRD Section
> #
> # Generally, xrd defaults are fine. So, no need to change them.
> #
>
> #-----------------------------------------------
>
> # The Xrootd Section
> #
> # Here we load the extended file system support for xrootd
> #
> xrootd.fslib /home/furano/xrootd/lib/arch_dbg/libXrdOfs.so
> xrootd.export /
>
> xrootd.prep logdir /tmp/prestage_log
>
>
> #-----------------------------------------------
>
> #-----------------------------------------------
>
> # The Open Load Balancer Section
> #
> # For managers, use the allow, port, and sched, and wait directives.
> # For Servers, use the path, perf, port, and subscribe directives.
> #
> # Indicate which hosts are allowed to connect to the olb (even if localhost)
> #
> #olb.allow host kan*.slac.stanford.edu
> #olb.allow host bbr-olb*.slac.stanford.edu
>
> # Tell the olb what port to use (server and manager)
> #
> olb.port 3121
>
> # To use load based scheduling, specify a load formula using sched
> #
> olb.sched cpu 100
>
> # Tell each data server what paths to export
> #
> olb.path s /
>
> # Tell each data server who to ubscrive to (i.e., the managers)
> #
> #olb.subscribe kanolb-a+ 3121
>
> # Tell each olb server to wait for the corresponding xrootd server
> #
> olb.wait
>
> # To effect load based scheduling, we must start a performance monitor
> #
> #olb.perf int 180 pgm /opt/olbd/bin/cur/XrdOlbMonPerf 120
>
> olb.prepmsg + $RID $NOTIFY $PRTY $OPTS $PFN
> olb.prep echo ifpgm /home/furano/xrootd/utils/mps_prep -c /home/furano/xrdtestmss/xrootd.cf.fabrizio
>
> # tell to the prestage cmd the location of the file which holds pre-staging queue (used by mps_prepare and mps_prestage program)
> mps.pstg.prtyfn /tmp/pre_stage.queue
> mps.pstg.logfn /tmp/prestage_log
>
>
> #-----------------------------------------------
>
> #-----------------------------------------------
>
> # The MPS Section
> #
> # Here code the relevant dorectives to control migration, purge, and staging
> # Most of the defaults are likely wrong. The typical ones to specify are:
> #
> # Where error messages go via mail and how often they should go
> #
> mps.adminuser = furano
>
> mps.msscmd = /home/furano/xrdtestmss/mymssgwcmd.sh
> mps.mssstat = stat
> mps.xfrcmd = /home/furano/xrdtestmss/mymssxfr.sh %sfn %tfn
>
>
> # For migration, how long to wait between runs, how long a failure is to be
> # recognized (after which the operation is retried). how often purge should
> # run, and the high/low purge thesholds.
> #
> mps.migr.rmfail_time = 129600
> mps.migr.waittime = 600
> mps.purg.waittime = 3600
> mps.purg.lousedpct = 80
> mps.purg.hiusedpct = 80
>
> # For pre-stage, we generally want to indicate the maximum number allowed
> # at one time and the command to use to transfer data from the mss
> #
> mps.pstg.max_pstg_proc = 3
> mps.pstg.pstgcmd = /home/furano/xrootd/utils/mps_Stage -i -d -c /home/furano/xrdtestmss/xrootd.cf.fabrizio
>
> # Generally, for all component, we need to indicate who the MSS transfer user
> # is, the target host and port. Usually, we limit retries to two.
> #
> mps.xfrhost = pcbabar9
> mps.xfruser = furano
> mps.xfrport = 2021
> mps.stage.max_retry = 2
> mps.debug = 4
> #-----------------------------------------------
>
>



Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
July 2009
June 2009
May 2009
April 2009
March 2009
January 2009
December 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004

ATOM RSS1 RSS2



LISTSERV.SLAC.STANFORD.EDU

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager

Privacy Notice, Security Notice and Terms of Use