Is 2.96 a lot faster?

[rseiler]

Every month, I do an automated (same settings) multi-volume full backup that's been taking between 5:15 (hours:minutes) and 5:30 in recent months (it's been a long time since it's been much less than that due to a gradual increase in what's being backed up over time).

Today, it took 4 hours.

At first, I thought it errored out, but no, it did both volumes and completed with error code 0 as usual.

Then I thought it must not have backed up as much, even though I knew what was on these drives doesn't dramatically fluctuate from month to month. But no, the total sectors it backed up actually went up a little this month.

So then I looked at the IFW history log to see if there was any hint, but not really (I install new versions when they come out, so last time I had 2.95). The note about VSS seemed to have possibilities, but IFW still uses Phylock in my case.

Is this something in the "Other potential changes, updates and enhancements" or is there some other explanation? The machine hasn't changed except an insignificant difference in what's backed up.

[Brian K]

Can you check your compression? Ver 2.96 seems to use Enhanced Speed - A as the default compression. Earlier versions used Standard Compression as the default, which was slower.

[rseiler]

Wow, that must have been it, great catch. Sure enough, if I run the UI and look at it, it's Enhanced Speed A, which the manual says is the default.

Since I don't use the /comp switch in my batch, which is how I ran the backup, that's what it must have inherited.

The manual says that A/B "offer decent compression with the emphasis on back up speed over backup file size. Backup files will normally be compressed less than the Standard option."

My backup results in a file in excess of 200GB, so I think it's a good sampling for compression. Its size is right on par with the months previous, so changing this setting was a great move. I wish I'd even thought of compression before, as it would have saved so much time.

[mjnelson99]

Thanks for this post. I would not have caught that change.

As it is, I looked for and changed it immediately.
Mary

On 6/7/2015 4:19 PM, rseiler wrote:
> Wow, that must have been it, great catch. Sure enough, if I run the UI and look at it, it's Enhanced Speed A, which the manual says is the default.
>
> Since I don't use the /comp switch in my batch, which is how I ran the backup, that's what it must have inherited.
>
> The manual says that A/B "offer decent compression with the emphasis on back up speed over backup file size. Backup files will normally be compressed less than the Standard option."
>
> My backup results in a file in excess of 200GB, so I think it's a good sampling for compression. Its size is right on par with the months previous, so changing this setting was a great move. I wish I'd even thought of compression before, as it would have saved so much time.
>
>

[jack450]

This seems like the appropriate place to ask what I'm sure many will regard as naive or uninformed, but as a photographer, I realize that compressing image files (photographs) actually deletes some of the information in the image, although the deletion of the information is not notceable to the naked eye. I'm curious as to how compressing a data image does so without deleting some of the information, and unlike looking at a photograph, the deleted informtion (if that's what compression does) might actually be something important. I'd be interested in any comments that don't require an engineering degree to understand.

Jack Greenberg

[TeraByte Support]

there are different compression methods, lossy and lossless. you can search
those terms to learn about them.


"jack450" wrote in message news:9735@public.image...

This seems like the appropriate place to ask what I'm sure many will regard
as naive or uninformed, but as a photographer, I realize that compressing
image files (photographs) actually deletes some of the information in the
image, although the deletion of the information is not notceable to the
naked eye. I'm curious as to how compressing a data image does so without
deleting some of the information, and unlike looking at a photograph, the
deleted informtion (if that's what compression does) might actually be
something important. I'd be interested in any comments that don't require
an engineering degree to understand.

Jack Greenberg

[Bob Coleman]

But isn't that image compression a completely different thing than file compression normally of interest here?

Isn't the image compression designed to produce a usable image of a smaller size? Once this is done, you don't decompress the image do you?

Isn't true that the result of compression used by the image products is only for saving space and isn't of any use until is decompressed during restore? Wouldn't the same be true of zip files and so forth?

Isn't the basic answer to the question that image compression is designed to produce a directly usable result while file compression is designed to save space during storage, but the compressed file can't be directly used without being first decompressed?

[TeraByte Support]

compression is almost always to save space (on slow media could save time).
it always requires something to decompress it (even for pictures to show
based on the image format). Reducing picture image quality is still
compression (lossy compression).



"Bob Coleman" wrote in message news:9737@public.image...

But isn't that image compression a completely different thing than file
compression normally of interest here?

Isn't the image compression designed to produce a usable image of a smaller
size? Once this is done, you don't decompress the image do you?

Isn't true that the result of compression used by the image products is only
for saving space and isn't of any use until is decompressed during restore?
Wouldn't the same be true of zip files and so forth?

Isn't the basic answer to the question that image compression is designed to
produce a directly usable result while file compression is designed to save
space during storage, but the compressed file can't be directly used without
being first decompressed?

[Bob Coleman]

Yes, but the original question on this subject seemed to reflect a concern that the compression done when creating a backup might lose important information. Isn't it true that the type of compression done when creating a backup doesn't delete anything that can't be recovered when reversing the process (decompressing)?

Might also be worth noting that "image" as in "picture" and "image" as in "backup" are quite different things (I think).

[TeraByte Support]

yes, backup would use lossless compression (no data removed).


"Bob Coleman" wrote in message news:9739@public.image...

Yes, but the original question on this subject seemed to reflect a concern
that the compression done when creating a backup might lose important
information. Isn't it true that the type of compression done when creating
a backup doesn't delete anything that can't be recovered when reversing the
process (decompressing)?

Might also be worth noting that "image" as in "picture" and "image" as in
"backup" are quite different things (I think).