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Backup Exec - Which IO size and R/W ratio is used or seen during backup?

Created: 04 Feb 2014 | 4 comments


i am sizing a new backup infrastructure.

In particular the landing zone (SAS 15K Drives).

Now i want to know which values can i

calculate with during a File Server Backup. What is happening (or how is data written at the


- which IO size will be used (will be seen) during a default full backup with default settings

and NTFS on 2008 R2?

- which read write ratio during a symantec backup exec 2012 full backup 

will be measured?

With both raw values i would be able to size a good landing space.

Thanks in advance


Operating Systems:

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pkh's picture

I am not aware that any of the data that you want is published.  You should log a support case with Symantec to get the answers that you want.

LucasS's picture

hmm, ok. But it is not competitive data or something.

I hope you get me right. The values i am asking for

are only depending an the behaviour of the specific software.

e.g. Symantec BUE is sending IO Sizes of 64 to the disk,

then it would not be the fault of the product if the

supplier is making a wrong sizing or something else.

I am only asking for values in "default" configuration after

setup is finished.

When a customer asks you "How long will the backup take" so

you will never be able to guarantee him a time windows.

But you are able to cummulate different values. The speed

of disks in MByte/sec (sas/sata), the speed of different MB/s depending

on the ratio and you could tell him the speed depending of the IO Size 

of the Application.

And this is what i am looking for plus r/w ratios of a simple full b2d task.

Thanks in advance


pkh's picture

The speed of the backup does not only depend on the disk.  Other factors comes into play.  The CPU and I/O contentions on the remote server and media server, the saturation of the network, how badly the resource disk is fragmented, what backup methods are used, etc.

LucasS's picture

I am aware of that!

I want only know what the usual IO Size of the data stream of the 

Symantec Backup is.

Nothing else!

The rest i will calculate myself.