Hi Bryan, in 4.1 AFM uses multiple threads for reading data, this was different in 3.5 . what version are you using ?
thx. Sven On Mon, Oct 6, 2014 at 8:36 AM, Bryan Banister <[email protected]> wrote: > Just an FYI to the GPFS user community, > > > > We have been testing out GPFS AFM file systems in our required process of > file data migration between two GPFS file systems. The two GPFS file > systems are managed in two separate GPFS clusters. We have a third GPFS > cluster for compute systems. We created new independent AFM filesets in > the new GPFS file system that are linked to directories in the old file > system. Unfortunately access to the AFM filesets from the compute cluster > completely hang. Access to the other parts of the second file system is > fine. This limitation/issue is not documented in the Advanced Admin Guide. > > > > Further, we performed prefetch operations using a file mmafmctl command, > but the process appears to be single threaded and the operation was > extremely slow as a result. According to the Advanced Admin Guide, it is > not possible to run multiple prefetch jobs on the same fileset: > > GPFS can prefetch the data using the *mmafmctl **Device **prefetch –j > **FilesetName > *command (which specifies > > a list of files to prefetch). Note the following about prefetching: > > v It can be run in parallel on multiple filesets (although more than one > prefetching job cannot be run in > > parallel on a single fileset). > > > > We were able to quickly create the “--home-inode-file” from the old file > system using the mmapplypolicy command as the documentation describes. > However the AFM prefetch operation is so slow that we are better off > running parallel rsync operations between the file systems versus using the > GPFS AFM prefetch operation. > > > > Cheers, > > -Bryan > > > > ------------------------------ > > Note: This email is for the confidential use of the named addressee(s) > only and may contain proprietary, confidential or privileged information. > If you are not the intended recipient, you are hereby notified that any > review, dissemination or copying of this email is strictly prohibited, and > to please notify the sender immediately and destroy this email and any > attachments. Email transmission cannot be guaranteed to be secure or > error-free. The Company, therefore, does not make any guarantees as to the > completeness or accuracy of this email or any attachments. This email is > for informational purposes only and does not constitute a recommendation, > offer, request or solicitation of any kind to buy, sell, subscribe, redeem > or perform any type of transaction of a financial product. > > _______________________________________________ > gpfsug-discuss mailing list > gpfsug-discuss at gpfsug.org > http://gpfsug.org/mailman/listinfo/gpfsug-discuss > >
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