Is reading from remote networked memory mapped file or device block faster than reading from Local 7200rpm HDDs?

Question

Or rather how does remote RAM compare against local Disk access? If the answer is "it depends", what are the conditions? Data access patterns, ratio of read-to-writes, distance etc.

Finally, what if the local disks are NetApp filers?

Thanks.

Answer 1

In general the local HDD will be faster, as the remote connection will be limited by the network bandwidth + protocol overhead.

If "local" (they're not really local if they're on a remote netapp) are netapps, they will be generally slower than remote RAM. Since netapps will most likely have the same network bottleneck + protocol overhead, plus file system overhead (nfs/smb), and most likely some sort of RAID overhead.