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Hi Patrick, Yes, the analysis is correct. You can set it up to allow deletions but disallow creation of new files via the redirector. Andy ----- Original Message ----- From: "Yang, Wei" <[log in to unmask]> To: "Patrick McGuigan" <[log in to unmask]> Cc: "xrootd-l" <[log in to unmask]> Sent: Tuesday, June 22, 2010 5:07 PM Subject: Re: Data Migration issues >I think you only need to change the configuration for the data server. >Redirector gets space info from cmsd on data servers. With cms.space, you >can still _write_ to the data server if you access it directly. But if you >ask the redirector to choose a data server for you for writing, the >redirector won't choose this particular data server. > > regards, > Wei Yang | [log in to unmask] | 650-926-3338(O) > > > On Jun 22, 2010, at 4:59 PM, Patrick McGuigan wrote: > >> Thanks Wei, >> >> I had thought that something like this method would be available, does >> your suggestion require a specific configuration in the redirector? We >> are using the defaults with respect to how the redirector chooses >> dataservers. >> >> Regards, >> Patrick >> >> On 06/22/2010 06:54 PM, Yang, Wei wrote: >>> Hi Patrick, >>> >>> If you set all.export path to readonly, you won't be able to delete. I >>> never tried any of this because but here is an idea: You may use >>> cms.space directive to set the minimum space required for the data >>> server to be writeable, and set a high number (above the total space of >>> that data server) so that redirector always think the data server runs >>> out of space. In that case, you can keep on deleting without worrying >>> about new data getting written to it. >>> >>> regards, >>> Wei Yang | [log in to unmask] | 650-926-3338(O) >>> >>> >>> On Jun 22, 2010, at 4:20 PM, Patrick McGuigan wrote: >>> >>>> Hi, >>>> >>>> >>>> I am preparing to replace 6 smaller dataservers with 2 much larger >>>> systems and I am curious if anyone has advice on making the transition. >>>> There is about 40TB of data currently on the smaller dataservers. >>>> >>>> A couple of caveats: >>>> 1) The existing data is organized in cache groups on the dataservers >>>> and >>>> the cgroup information will need to propagate to the new dataservers >>>> >>>> 2) The smaller dataservers are in a production system and I want to >>>> minimize any downtime associated with data on these servers. >>>> >>>> 3) A sizable portion of the 40TB is no longer relevant to the >>>> production >>>> system and potentially could be deleted (or at least not migrated) >>>> >>>> >>>> It eases my burden if I can delete data from all the production >>>> dataservers at the same time. However, if I delete data from the 6 >>>> servers that will be migrated, I don't want new data to take its place. >>>> >>>> >>>> I was hoping that I could somehow setup the existing dataservers in a >>>> readonly configuration but still be able to delete data via the >>>> redirector (actually from a FUSE client talking to a CNS service on the >>>> redirector). Is this possible? >>>> >>>> >>>> From my reading, I can make the dataservers readonly by altering the >>>> all.export line: >>>> >>>> all.export /xrd readonly >>>> >>>> But I am not sure if this still allows deletions. >>>> >>>> Also, does the use of oss.cache directives affect the readonly status? >>>> >>>> >>>> If anyone has experience with performing this type of migration, or if >>>> anyone has suggestions, I would be very thankful to hear from you. >>>> >>>> Regards, >>>> >>>> Patrick >>>> >>>> >>> > >