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Hi Patrick, No, you got that right; the problem is that this applies to the redirector as well and you needed to restart it. Andy ----- Original Message ----- From: "Patrick McGuigan" <[log in to unmask]> To: "Andrew Hanushevsky" <[log in to unmask]> Cc: "Yang, Wei" <[log in to unmask]>; "xrootd-l" <[log in to unmask]> Sent: Thursday, June 24, 2010 7:04 PM Subject: Re: Data Migration issues > Hi Andy, > > This doesn't seem to be working for our systems? > > I included: > > cms.space min 15t 15t > > in the configuration, and restarted the dataservers yesterday. I checked > one > of the data servers and saw that files were written today on the system. > > I take the config line to mean that there must be at least 15TB available > before > the dataserver will write. Do the two values have to be different? > > Patrick > > > On 06/22/2010 11:03 PM, Andrew Hanushevsky wrote: >> 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 >>>>>> >>>>>> >>>>> >>> >>> >