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Hi Matevz, I think one use case is to have Xcache completely replacing the storage at a site. I see the pain of using two paths, one for read (via xcache) and one for write (bypassing xcache). We can sort this out in application level (such as having atlas pilot to prefix xcache url for read but not for write) but it would be nice to introduce this capability to the xcache so that applications donıt have to think of it. You raised the concern about authorization for writing. Until we sort out proxy delegation, we donıt have a perfect solution. But maybe we can just assume for now the x509 proxy used by xcache will be used, and sort this out later? Andy mentioned to me that pass through is possible. Tengıs approach is interesting but wonıt solve the immediate problem - even if we check in his code now, it takes forever for ATLAS to start using that release of xrootd. regards, -- Wei Yang | [log in to unmask] | 650-926-3338(O) -----Original Message----- From: Matevz Tadel <[log in to unmask]> Date: Friday, March 2, 2018 at 6:33 PM To: Wei Yang <[log in to unmask]>, Fabrizio Furano <[log in to unmask]>, Andrew Hanushevsky <[log in to unmask]> Cc: xrootd-l <[log in to unmask]>, Mihai Patrascoiu <[log in to unmask]>, Matevz Tadel <[log in to unmask]> Subject: Re: Testing the XrdPss with cachelib - Issues with writing >Hi Wei, > >On 3/2/18 1:33 AM, Yang, Wei wrote: >> Dittos > >Can you please elaborate ... in what way would you use this in ATLAS? > >Cheers, >Matevz > >> -- >> Wei Yang | [log in to unmask] | 650-926-3338 >> >> ________________________________________ >> From: [log in to unmask] <[log in to unmask]> on behalf of Fabrizio Furano <[log in to unmask]> >> Sent: Friday, March 2, 2018 1:29:59 AM >> To: Hanushevsky, Andrew B. >> Cc: xrootd-l; Mihai Patrascoiu; Matevz Tadel >> Subject: Re: Testing the XrdPss with cachelib - Issues with writing >> >> Hi Andy, >> >> thanks for the hints. My opinion is that a passthrough option would be >> a very big plus for the caching proxy, and I was sincerely surprised >> by this limitation. >> >> For some of our use cases I believe that we will start using it without >> caching, as I can't imagine how to give a transparent service by having >> to force clients to use different paths for reading and writing. >> >> What do you think ? >> >> Thank you >> Fabrizio >> >> On 03/01/2018 06:09 PM, Andrew Hanushevsky wrote: >>> Correct, we don't support a writable cache because that's not what a cache is all about. Does the origin support writes? If so, >>> we could potentially provide a cache passthrough option. Otherwise, if the readable and writable path differ, he could have run >>> two proxies -- one caching for read access and a passthru proxy for writing then setup a redirect directive in the primary proxy >>> (i.e. the one that will be initially used) to direct writes to the passthru proxy based on path. >>> >>> Andy >>> >>> On Thu, 1 Mar 2018, Fabrizio Furano wrote: >>> >>>> Hi, >>>> >>>> Mihai is trying to setup a small Pss machine that also works as a cache. >>>> >>>> For reading it seems to work fine, yet it stubbornly refuses to write files with >>>> this error: >>>> >>>>> 180301 17:27:38 13788 XrdFileCache_Manager: debug Cache::Attach() >>>>> root:[log in to unmask]:1094//eos/xdc/testing/hello.txt?&oss.asize=14&oss.lcl=1 location: <deferred open> >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 ofs_fstat: fn=/eos/xdc/testing/hello.txt >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdResponse: 0100 sending 46 data bytes; status=0 >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100 req=write dlen=14 >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100 fh=0 write 14@0 >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 ofs_write: 14@0 fn=/eos/xdc/testing/hello.txt >>>>> 180301 17:27:38 13788 ofs_write: root.3008:20@xdc-test-fst1 Unable to write /eos/xdc/testing/hello.txt; operation not supported >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100 discarding 0 bytes >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdResponse: 0100 sending err 3005: Unable to write >>>>> /eos/xdc/testing/hello.txt; operation not supported >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100 req=close dlen=0 >>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 ofs_close: use=1 fn=/eos/xdc/testing/hello.txt >>>> >>>> If we remove the directive pss.cachelib then writes work instead. >>>> >>>> Can anyone give us a clue please ? >>>> >>>> Thank you >>>> Fabrizio and Mihai >>>> >>>> >>> >> >> >> ######################################################################## >> Use REPLY-ALL to reply to list >> >> To unsubscribe from the XROOTD-L list, click the following link: >> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-L&A=1 >> >> ######################################################################## >> Use REPLY-ALL to reply to list >> >> To unsubscribe from the XROOTD-L list, click the following link: >> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-L&A=1 >> > ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the XROOTD-L list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=XROOTD-L&A=1