On Tue, 12 Oct 2004, David V. Corbin wrote:
Subject: RE: classiccmp server hardware
>>> Has anyone mentioned that if the OS or
hardware or horrid
>>> software goes astray and writes crap all over the disk,
>>> RAID doesn't save you but the 'periodic rsync' approach does?
I would be inclined to phrase that as "May"
save you, rather than "Will".
Absoluetely -- it's even possible for rsync to propagate data
loss! (--delete) But the very top of the pile of reasons for
data loss is human error, and a simple "recent copy" solves 99%
of that.
There is no single system that solves all problems. Since
complexity often causes humans to make more mistakes, and
inherently decreases MTBF, and costs more, simplicity is usually
most optimum (sic), barring other EXPLICIT constraints.
* At work (university computer lab) I have students with home
dirs (many files, various sizes) and video projects (few files,
HUGE). Major worry: student foolishness, second worry, other
human data loss, tertiary, the usual (hardware failure, etc).
Long-term archiving not needed. Heterogenous network (pc,
mac, linux).
My solution here is two servers, weewee and fluffy, both terabyte
RAID5 (serial ATA, 3ware, SuSE 9.0) 2.8GHz, 4GB RAM. Weewee runs
SAMBA, mounts homes and video home. UPS with software support. It
also runs an rsync/cp -a script that generates rotating hourly
snapshots of everything (except video); students can recover
files hour by hour. Fluffy takes a daily snapshot of weewee,
and rotates that once per day, and maintains the last 10? days
of data. There is no off-line backup. Various desktop machines
backup into weewee also, get rotated, etc. Weewee and fluffy
have a private gigabit ethernet with crossover cable; copying
video data can take 10 - 300 minutes via cron. Who cares? Cheap
($3K/server) nearly zero maintenance. Load average rarely exceeds
.1.
* At home everything exists on my laptop, including
wps.com. Major worries: support fancy data-dispersion scripts,
human data loss, last, hardware. Rsync "mirroring" between three
(soon four) net-wide machines. Paper copies. Occasional CDRs
mailed to friends. Archiving back to 1994 (sporadic).