In my previous post, I indicated that we are backing up to an RDX device,
which we ordered with our model S914 and is housed in the server chassis. I
think it uses a USB 3 interface to the server. I've been pleased with the
setup. I think it is a good option if your storage is under 5 terabytes.
But I'm not sure how it might compare with a VTL. One of my reasons for
following up with this message is to solicit feedback for comparison
purposes. Please feel free to suggest comparisons and contrasts.
It appears to me that an RDX drive is comparable to a VTL in that:
- One can restore a SAVE 21 image from either during an IPL.
- One can use IBM i commands, or BRMS, or write your own backup routines,
or choose ISV software that supports either device.
It appears that an RDX drive may contrast with a VTL in that:
- The RDX drive appears as a virtual optical device, whereas I presume that
the VTL appears as a virtual tape device (please clarify if otherwise).
- RDX drives are removable, whereas my understanding is that a VTL is a
configured disk array.
I like that you can eject the RDX drive, insert an alternate, and take it
I like virtual optical in that your save operations can simply replace
previous save "labels", which if I understand correctly, eliminates the
need for a deduplication operation. We typically use day of week (Sunday -
Saturday) and BOM for beginning of month in our label names. I assume that
virtual tape emulates physical tape in that new save operations typically
append, rather than replace (but I'd like clarification if otherwise).
In regard to cloud storage, I fear that FTP may have gotten a bad rap in
this thread. Maybe VTL software uses FTP under the covers for cloud
storage? I haven't had any problems restoring SAVF files from an AWS FTP
site, for example.
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