dnb@brandeis.csnet (David N. Blank) (02/01/88)
Greetings,
I have a "What if..." question that you might be able to help me
with. Currently, we do level zero backups for our twelve odd SUN (2/3)
workstations (running NFS) over our ethernet (via rmt) to our standard
DEC tape drives residing on a VAX. This takes an eternity (ok, maybe
not an eternity, but it is a good six+ hour job) during which all of
the workstations must remain idle. Surely there must be a better way.
One way might be to hook up (while doing the backup) one of the DEC
tape drives directly to a sun, but I am unsure of the feasibility of
this alternative. Is this possible? What hardware/connectors would I
need for this? Thanks for your help.
Peace,
David N. Blank (dnb@brandeis.csnet | blank@brandeis.bitnet)
Assistant SysAdmin
Brandeis University Computer Science
"And you may ask yourself:
HOW DO I WORK THIS THING?"
-- David Byrne, Talking Heads
chris@mimsy.UUCP (Chris Torek) (02/02/88)
In article <11570@brl-adm.ARPA> dnb@brandeis.csnet (David N. Blank) writes: >... Currently, we do level zero backups for our twelve odd SUN (2/3) [twelve is even, but I suppose a Sun two-thirds is odd :-) ] >workstations (running NFS) over our ethernet (via rmt) to our standard >DEC tape drives residing on a VAX. This takes an eternity .... >Surely there must be a better way. There is one better way that is very cheap, although it requires that you have 4.3BSD on one of those Vaxen. Take your 4.3BSD /usr/src/etc/dump and compile and install it on your Suns. (Keep the old /etc/dump and /etc/rdump in case of emergency. Note also that Sun links /etc/rdump to /etc/dump, Sun having noticed that rdump can write local files just as easily as can dump.) Next, increase the `tcp_sendspace' variable on your Sun kernels to (at least) 8K, and reboot: % su Password: # adb -w /vmunix /dev/kmem tcp_sendspace/D tcp_sendspace: tcp_sendspace: 4096 tcp_sendspace/W 0t8192 tcp_sendspace: tcp_sendspace: 4096 = 8192 .?W 0t8192 tcp_sendspace: tcp_sendspace: 4096 = 8192 $q # shutdown ... # fastboot Now run rdump and note that it goes at least twice as fast. If you leave out the tcp_sendspace step, however, it will run at a mere five tape blocks per second. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris