Cluster Computing and MapReduce Lecture 3

[ForexReviewsCentral]

a bit confusing...

[StroonsGlen]

please! ayaw kalimti ang slide, pahingi, gamiton nako sa ako classe.

[exn666]

бойан

[VondaFononono]

The Google File System is not that complicated as we thought.

[tivrfoa]

the link is broken 

[ahavill]

At the beginning of the lecture, he says that NFS is a POSIX file system. It isn't. I'm sure he just misspoke and meant to say that it's a networked file system popularly used with POSIX operating systems.

[vermaabhishekp]

NFS is a POSIX-*compliant file system*.

[ahavill]

Thanks for the clarifying his exact words.

However, NFS isn't POSIX *compliant* either. Open Group's XNFS specs explain how NFS semantics differs from POSIX/SUS in over 10 pages of detail.

[yanglian]

good.

how gfs helps MapReduce

[edunagin]

In the latter part of the presentation, there is talk and notes about file deletion. It was said that the file that is to be deleted is given a hidden name and then at a later time when the Master Server is slow, Then it can then delete these hidden files.

This does not make sense to do a seperate operation to delete files for the hidden file names will simply be written on when the controller need the space of the drive.

[vermaabhishekp]

In the paper, it is described that if the user retries to delete a file, then it is immediately deleted. The gfsutil actually has different parameters to force delete a file immediately in order to reclaim space immediately.