Re: [Networker] SUN X4500 'Thumper' as a storage node?
2007-04-24 11:04:06
On Apr 24, 2007, at 1:36 AM, Oscar Olsson wrote:
On 2007-04-23 14:15, Stan Horwitz revealed:
SH> We don't currently do any kind of disk-to-disk-to-anything
backups. I do not
Ive been following this thread for a while now. What I can't figure
out is
why one would want to stage from disk to disk when it comes to
backups?
Why not write to the secondary disk storage (i.e. cheap disk) right
away?
I guess we are doing that, in a sense, by using RAIDed storage. One
of the benefits of the design I am implementing (and its probably the
most important one for us) is that backing up from production disk
storage to secondary disk storage before going to tape gets the
primary data copied off-site and it should do it much faster then is
currently possible. The tape library and NetWorker server here sit in
a different building then our primary servers.
I am hoping to be able to stream the data from several large servers
to disk (off-site) cheaply and then shoot that data at our Sony
PetaSite's tape drives faster than going direct from servers to tape.
This allows me to address another concern (I hope) that we aren't
getting nearly enough throughput to our tape devices. I also want to
take some of the load off my NetWorker server by sending backup data
for some of our largest systems to a different storage node on the
same tape library. Our backup server is frequently overloaded.
There are several cheap storage systems (for instance the systems from
http://www.infortrend.com) where they just supply a disk array,
where you
then buy off-the-shelf products such as actual disks and controller
RAM
yourself. In terms of I/O performance, even these systems should be
more
than enough for backups. So why do people use tiered disk for
backups, or
VTLs? To me, the point of VTL is just to work around backup
products that
aren't good at working with file systems or block devices as
targets of
backup data. VTLs just seem to limit the functionality of the
actual disk,
by emulating library behavior, with its set of limitations such as
random
paralell I/O. Why not just use adv_file devices instead, and then just
stage that data to tape?
Have you looked at the price of a Sun X4500? Its very attractive and,
despite its name, its really a large storage array with a Sun (AMD
Opteron) tacked onto it. Academic pricing for an X4500 is also very
attractive. In a sense, a Sun X4500 IS a great approach to the
solution you just outlined. I am not going to be using my X4500 as a
VTL because I am not convinced that a VTL would be a good fit in this
environment.
Also, even with the falling price of disk storage, the cost per GB
of tape and its essentially unlimited capacity, still makes it the
medium of choice for long-term storage and off-siting.
To sign off this list, send email to listserv AT listserv.temple DOT edu and type
"signoff networker" in the body of the email. Please write to networker-request
AT listserv.temple DOT edu if you have any problems with this list. You can access the
archives at http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER
|
|
|