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Please help with a through h . Answer correctly with explanation. Image is better. Problem 1 : A bunch of distributed file systems questions. In
Please help with a through h Answer correctly with explanation. Image is better.
Problem : A bunch of distributed file systems questions.
In this problem you will explore the strengths and weaknesses of two commercially successful dis
tributed file systems AFS and NFS Specifically, you will look at the implications of state or lack thereof
at the server when several clients are writing to the same file.
Recalling from the lecture the semantics of NFS server the original version, ie no leases it does not
know when a client opens a file for writing nor when the client is done writing and closes the file. Because
of that, NFS requires that the client writes thorough all changes ie every time a client writes a byte to the
file, the client sends the appropriate block eg KB to the server that writes it synchronously to the disk.
The AFS server, on the other hand, keeps a list of all clients that have a file open. The client modifies
a local copy of a file and only when it closes the file are the dirty blocks sent to the server. The server then
looks up all the clients that have a local copy of the same file and sends them an invalidation message via a
callback. This message lists all the blocks that have been modified. The clients have to contact the server if
they want to get the latest version of the data.
Assume a sequence of system calls listed below at four elients that all open the same file stored on
a file server. The file is initially empty. The time increases such that The syscall
write data means that the data written the file whose descriptor Answer the following
questions. Give all scenarios whenever possible and briefly explain your answer.
Assuming file stored server, what its content
Assuming file stored AFS server, what its content
Assume a network failure occurred between and and never recovered the elose system call failed
client
What the content the file server?
What its content AFS server?
Assume a network failure occurred between and and never recovered the write failed client
and close failed clients and
What the content the file server?
What its content AFS server?
Now assume that the server went down between and but everything else was functioning well. took
sufficiently long for the server come back that all the clients finished their applications they
didn't handle a failed write and close system calls happily believing their data was saved.
What the content the file when the server came finally
When the AFS server came finally
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