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Hi Matevz, >> Also not caching (hence just tunnelling) a file that is opened for write would >> be fine. At the end most of the heavy use cases are just WORM, and whoever >> enables this is supposed to be aware of the limitations... hopefully. > > Do you need tunneling or is redirection good enough? Good question. Tunnelling is the way to go for a totally generic use case. To make it really super pwoerful, I'd also welcome if there was a way to pass the information of XrdSecEntity to Pss, just to foresee some form of credentials passing that we may design together. I believe that the project has enormous potential if we can avoid workarounds at the client/app side. Cheers Fabrizio > > \m > >> Also limiting the prohibition to opens for append/mpodify would be fine I guess. >> >> Fabrizio >> >> >> >> >> >> On 03/02/2018 10:46 AM, Andrew Hanushevsky wrote: >>> Hi Fabrizio, >>> >>> The reason we didn't do it for a disk caching proxy is because cache synchrnization is extremely difficult as you may be reading >>> as well as writing the file. The memory caching proxy does support reading and writing as synchnizing a memory cache is trivial. >>> So, even if we did a passthrough option it would be very restrictive (i.e. you can either read the data or write the data but >>> not both unless the cache is disabled and opening a file for writing would necessarily have to flush the cache for that file). >>> That we could also do. >>> >>> Probably the fastest solution here (at the moment) is to write an ofs plugin wrapper for the caching proxy that checks for write >>> opens and does the appropriate redirection. We can do that also by extending the static redirect directive to differentiate >>> between read paths and write paths; thuogh that opens the proxy to cache synchronization issues unless files are not bth read >>> and written at the same time. >>> >>> Andy >>> >>> On Fri, 2 Mar 2018, Fabrizio Furano wrote: >>> >>>> 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