Question

tape drive utlization , lt09 - compression not working due to encryption

  • 12 February 2024
  • 10 replies
  • 42 views

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hi , 

we have hyperscale with encryption enabled and we are having aux copy to tape with below settings 

basically each tape should give aroung 40 tb after compression but we are only getting 15 tb  , do we need to disabled the encryption .

i can see hardware encryption is enabled in the data path setting for tap e 

 


10 replies

Userlevel 1
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Hi Ajal,

 

Encryption is important for data security. If you wish to disable it , you can. But disabling encryption will not be helping us as this is not deduplication data (Tape does not support deduplication).

 

We would recomend you to enable hardware compression (if not already enabled) if your tape vendor supports it.

Configuring Hardware Compression (commvault.com)

 

Further can you please help us understand how are we reaching 40TB figure as expectation ?

 

Regards,

Suleman

 

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@SMD  hardware encryption is already in place , 

 

now we compression enabled for DDb enginer by default, so when we are using software encryption hardware encryption will not work for aux copy right? 

 

for lt09 for uncompressed data 40tb space 

 

Userlevel 1
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@SMD  will this work , disabling the compression from the below option 

and make sure hardware encryption is enabled 

 

this way we can get the expected utlization right ?

Userlevel 1
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Hi @Ajal 

 

You are on a deduplicated copy property.  We can disable the below option if it is from tape copy.

 

Also, can you please confirm if this is true for Tape with encryption enabled ?

 

Idea is to make sure we use Hardware encryption ,hardware compression and let Tape library take care of the rest.

 

Regards,

Suleman

 

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@SMD i dont know what you meant below

You are on a deduplicated copy property.  We can disable the below option if it is from tape copy.

 

the screenshot was of ddb engine property

if i disabled this software compression will stop that way hardware compression can work

 

 

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@Ajal  Tape copy and Deduplication copy is different. Also if we have software and Hardware compression/encryption selected, system will always prefer hardware.

 

We can make chnage on teh Tape copy, not on the deduplication copy.

 

Regards,

Suleman 

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@SMD  may b you didnt understand,

 

i have hyperscal pool and i have create aux copy from it to tape,”.

 

I can see in the document if software encryption enable in source hardware encryption may not work

may be you dont have information about this

 

thanks

Userlevel 1
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Hi @Ajai,

 

Apologies for the confusion.

 

If software encryption is enabled on the source, we can enable hardware encryption for the AUX and keep software encryption disabled. This will work.

 

Regards,

Suleman

Userlevel 1
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@SMD 

what about below , 

  • If you are performing an auxiliary copy operation to tape and the source copy has software compression enabled, you will not see any benefit from hardware compression. 

for hardware level compression to work , source copy has to plain and un compress state 

Userlevel 1
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Hi @Ajai 

 

Apologies for the confusion.

 

I went trhought the notes now

 

Notes

  • If you are performing an auxiliary copy operation to tape and the source copy has software compression enabled, you will not see any benefit from hardware compression.

  • If deduplication is enabled on the source copy and the copy uses software compression, there will be no saving from hardware compression on an auxiliary copy to tape. This is because the data has already been compressed on the source copy.

  • Software encryption will eliminate any hardware compression. Do not use software encryption when you enable or expect hardware compression of the data.

 

ref: Use Tape Drive Compression to Save Storage Space (commvault.com)

 

Here is no mention about encryption on the source copy must be disbaled but speaks about source copy should not have software compression enabled. We can disable software compression on source copy and monitor the outcome.

 

 

Regards,

Suleman 

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