Networker

Re: [Networker] SUN X4500 'Thumper' as a storage node?

2007-04-24 11:04:06
Subject: Re: [Networker] SUN X4500 'Thumper' as a storage node?
From: Stan Horwitz <stan AT TEMPLE DOT EDU>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Tue, 24 Apr 2007 11:00:36 -0400
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.

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