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Accepted
Kyle Hailey
Asked: 2011-07-01 16:40:07 +0800 CST

writing to opensolaris ramdisk over NFS

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I want to read and write to a ramdisk on OpenSolaris for performance testing purposes. The tests would be aimed at network transmission and I want to rule out disk performance. I set up the ramdisk on the NFS server, machine A, with

mkfile -nv 1000m  `pwd`/ramdisk

on a directory that was mounted via NFS onto machine B. Reading the ramdisk went fine, but writing to it, just overwrote the file. I then setup a ramdisk with

ramdiskadm -a ramdisk1 1000m

which I can write to fine but I can't access over NFS. The ramdisk is put on /dev/ramdisk which is a link to /devices/pseudo I added /devices/pseudo to /etc/dfs/sharetab and mounted it on machine B without error, but the contents of the directory on machine B are emtpy.

nfs solaris sun opensolaris

2 Answers

  1. Best Answer

    Here is the high-level recipe for what you want to do:

    1. Create ramdisk device (ramdiskadm)
    2. Format ramdisk device with a filesystem (newfs or zpool create)
    3. Mount ramdisk device on a mount point (mount, or automatically for ZFS)
    4. Export that mount point through NFS (man export fs, or zfs set sharenfs=on)
    5. Profit!

    mkfile doesn't create ramdisks, only files on some storage area. Since you want to test performance I don't see how it would help.

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  2. A much simpler solution: (thanks to Adam Leventhal for this tidbit)

    On Server

     share -F nfs -o rw /tmp

    On client:

       mkdir /tmpnfs
   mount -o vers=4,rsize=32768,wsize=32768 server:/tmp  /tmpnfs

    works like an in memory file system.

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