LTO6 Capacity

[20100]

Hi
Just got new V8 with new HP 1x8 G2 Autoloader (LTO6). the Tape library and Tape drive is running the latest HP firmware.
The Veeam server is running Windows 2012R2.
From the HP tape utility, we can confirm the hardware compression is ON, however Veeam thinks the capacity is 2.4Tb. Should be around 6.5Tb

Where else should we look to get the correct capacity to be recognised?

Note that we have the correct L6 barcode tape labels.

Thanks

[Dima P.]

Hi qq,
Veeam Tape Service displays the raw media size (without possible compression). Please bear in mind that if you are going to archive backups to tape, compression output might be close to zero unless you disable backup compression in the original backup to disk job.

[20100]

Thanks

So are you saying that it display the capacity without compression, but we should be able to fit more than 2.4Tb on the tape?
My understanding of hardware compression vs software compression is that hardware will put more data on the tape, regardless of the compression of the data itself. Usually you do not use both at the same time.

Here, with Veeam in the tape job definition, in the general settings the "Use hardware compression is available" is unticked as per recommendation, which means that we will never be able to store more than 2.4Tb!

[Dima P.]

we should be able to fit more than 2.4Tb on the tape?

Yes, with the enabled hardware compression in tape job settings.

hardware compression vs software compression is that hardware will put more data on the tape, regardless of the compression of the data itself. Usually you do not use both at the same time.

You can have both, but it may be a resource/time consuming at some point

If its possible you can check what is the best approach for your setup:
- Create a full backup of the VM with software compression disabled. Then fire this backup to tape with hardware compression
- Create a full backup of the VM with software compression enabled (default - optimal level should be enough). Then fire this backup to tape without hardware compression.
- Create a full backup of the VM with software compression enabled and run a backup to tape with enabled hardware compression

Compare the results: time of the backup to disk/tape, and the used space. If you are going to run the said tests, don’t forget to share the results with the community

[tsightler]

My understanding of hardware compression vs software compression is that hardware will put more data on the tape, regardless of the compression of the data itself.

I'm not sure if I'm following what you are saying. Veeam backups are generally compressed, and that usually means that trying to compress them again isn't going to give much savings. The compression numbers stated by hardware compression for LTO devices assume the data being sent to the drive is uncompressed and those algorithms will generally be able to achieve 2:1 (for LTO2 to LTO5) and 2.5:1 for LTO6.

LTO6 uses SDLC (also called LTO-DC), while previous LTO versions used ADLC. Both of these algorithms are based on good old "LZS" compression developed by Stac Electronic way back in the early 90s (late 80s maybe -- anyone remember Stacker disk compression software and the Stac vs Microsoft lawsuit?). The ADLC algorithm suffered from an issue that, when faced with already compressed data, the resulting data stream would actually be larger than the original, in many cases up to 15% larger. This means that, assuming you are backing up compressed Veeam files, it's going to almost always be better disable hardware compression on LTO-5 and older driver because the ADLC algorithm may very well use more space on the tape that without hardware compression. The exception to this is if you are backing up uncompressed Veeam files (for example when storing Veeam backups on a dedupe appliance) or if you are backing up files other than Veeam backups that might be compressible.

With LTO-6 the SDLC algorithm improves upon ADLC by recognizing already compressed data and simply passing it through without any alteration. This means that for LTO-6 drives you are generally safe to leave hardware compression on even when the source data is already compressed, although yet again, assuming you are backing up already compressed Veeam backup files, you're unlikely to see any benefit, but perhaps you might see a small increase. Certainly you're not going to see 2.5:1 or anything crazy like that. I've seen customers manage to get 2.6-2.7TB on a 2.5TB LTO6 media when using hardware compression.

[20100]

Thanks you both for your replies.

From what I read from tsightler, it looks like I was wrong on my assumption of tape size vs amount of data on the tape itself. So I might leave it as it is.
I was just surprised to see the tape as 2.4Tb from the Veeam perspective, as our previous backup solution shows the tape size as 6.5Tb when the tape is scanned (perhaps the info is on the barcode reader?!)
So, in practical terms, in means that if the backup on disk is greater than 2.4Tb more or less, I will need a second tape to copy it. This is were I was wrong, I thought I could fit up to 6.2Tb on it, but you corrected me.
I will probably need to split the disk backup onto several in order to stay 2.4Tb.

Cheers

[tsightler]

Yeah, some tape software shows the "compressed" capacity, but this is pretty misleading since it's based on the prediction that you will be backing up files that aren't already compressed. If, for example, you backed up nothing but JPG images, MP4 files or ZIP archives, you'll never get close to that 6.5TB. Since Veeam backups are already compressed, the chance of getting significant savings from the hardware compression is quite limited.

[cffit]

So from a VEEAM support suggestion, is it best to NOT use tape drive compression beings the VEEAM backup files are already compressed?

[veremin]

As mentioned above, if you're already compressing backups via VB&R, you're unlikely to see huge data reduction with hardware compression.

Though, you can disable VB&R compression, use hardware one, instead, and see which one suites you most.

Thanks.

[cffit]

I run two backup jobs each day. One is VM backups to tape, and one is Windows files to tape. It seems like I won't realize much saving on the VEEAM VM backups to tape, but I may on the files to tape. Is the tape drive's hardware compression enabled on the tape library, and an all-or-nothing feature? Or is VEEAM able to tell the tape drive which jobs to use hardware compression on?

[veremin]

Hardware compression is granular setting that can be enabled for a particular job. Thanks.

[Daithi]

Hi folks,

We use a LTO 6 drive. Our backups are compressed using the Optimal setting to disk. They are then copied to tape over the weekend.

From reading around it seems best not to enable compression on the Tape Drive itself? Is this correct?

[veremin]

Your post has been merged into existing discussion. Kindly, check the answers provided above and ask for additional clarification, if needed. Thanks.

[Daveyd]

All my VBR jobs are being written to Exagrid appliances. Each backup job is set to use "De-Dupe friendly" compression, which looking at Veeam reports is only 1.1x-1.2x. To meet our requirements for Monthly Full backups to tape, I created multiple tape jobs using a GFS media pool write a full backup of each job to tape.

We have an old LTO3 HP library that uses 400GB/800GB tapes. In each tape job under Compression, it states "We do not recommend enabling this option when backing up already compressed backup files". The issue I have is since there is very little compression at the backup level and it is not recommended to use Hardware compression, we are using A LOT of tapes to cut Monthly fulls to. In order to utilize fewer tapes, do I need to turn off De-dupe friendly compression at the backup job level or can I just use Hardware compression with the De-Dupe friendly compression enabled?

[PTide]

Hi,

In order to utilize fewer tapes, do I need to turn off De-dupe friendly compression at the backup job level or can I just use Hardware compression with the De-Dupe friendly compression enabled?

You can use both, however it may give some impact on performance.

Thank you.

[davidburke84]

Current Setup:
Using a physical Veeam server with Snapshot Backups (3Par).
Backups are going to an HP StoreOnce5100 with Storage Support (no Veeam compression)
2 LTO4 tape drives
10TB of data is being backed up and dedupping down to about 3TB.

My strategy is to have 1 full month of daily backups on the appliance and do a tape job once a month on the 1st that writes the latest full backup to tape.

When I write the backups to StoreOnce I do not do Veeam's built in compression. This is per best practice since HP will do a better job of this.

My question is this:
When I write my last full backup out to tape should I use compression within the Veeam job or do best practice and leave it uncompressed?

Does anyone else have experience with this particular setup?

Thanks.

[veremin]

When I write my last full backup out to tape should I use compression within the Veeam job or do best practice and leave it uncompressed?

It's up to you to decide which approach suites your needs best. Check the answers provided above, should give you some ideas. Thanks.

[davidburke84]

For anyone that has the situation I have stated above where you're not using the native Veeam Dedup to your storage repository and you're wondering if you should use hardware compression on the tape drive. Here's what I've found:

The tape backup is being done 6 hours after the weekly synthetic full and not doing tape backup of any incrementals. The current setup is one backup every night at 10PM. This backup is ~6.5 TB of data and all going to LTO3 tapes. 2 Tape drives with parallel processing.

Without compression:
runtime was 12 hours and 5 minutes and used 19 LTO3 tapes.

With compression:
runtime was 9 hours and 30 minutes and used 12 LTO3 tapes.

Both scenarios shows the tape drive as the bottle neck. I'm going to change my jobs to use the hardware compression and will report back any issues.

[Elefanten]

Hi

Using Veeam 9.5 and VMware 6.0
Tape Drive is LTO 4 - HP


Trying to backup the fileserver to only one tape.

Fileserver size is 956GB and have enabled the following settings :

-Reverse incremental backup job.
-Use hardware compression when available is turned on (Tape Job)
-Compression level set to None on the Backup job.

Still it could not transfer more than 850GB before it asked for second tape, i believed i could utilize the hardware compression on tape and with LTO 4 i could get closer to 1,5 TB ?
Did it not use the hardware compression at all, any chance for me to verify this ?

BR
Elefanten

[veremin]

Differences between both approaches (software and hardware compressions) are described above. So, kindly, take a look. Thanks.

[Marco.Teijido]

I'm not sure if I'm following what you are saying. Veeam backups are generally compressed, and that usually means that trying to compress them again isn't going to give much savings. The compression numbers stated by hardware compression for LTO devices assume the data being sent to the drive is uncompressed and those algorithms will generally be able to achieve 2:1 (for LTO2 to LTO5) and 2.5:1 for LTO6.

LTO6 uses SDLC (also called LTO-DC), while previous LTO versions used ADLC. Both of these algorithms are based on good old "LZS" compression developed by Stac Electronic way back in the early 90s (late 80s maybe -- anyone remember Stacker disk compression software and the Stac vs Microsoft lawsuit?). The ADLC algorithm suffered from an issue that, when faced with already compressed data, the resulting data stream would actually be larger than the original, in many cases up to 15% larger. This means that, assuming you are backing up compressed Veeam files, it's going to almost always be better disable hardware compression on LTO-5 and older driver because the ADLC algorithm may very well use more space on the tape that without hardware compression. The exception to this is if you are backing up uncompressed Veeam files (for example when storing Veeam backups on a dedupe appliance) or if you are backing up files other than Veeam backups that might be compressible.

With LTO-6 the SDLC algorithm improves upon ADLC by recognizing already compressed data and simply passing it through without any alteration. This means that for LTO-6 drives you are generally safe to leave hardware compression on even when the source data is already compressed, although yet again, assuming you are backing up already compressed Veeam backup files, you're unlikely to see any benefit, but perhaps you might see a small increase. Certainly you're not going to see 2.5:1 or anything crazy like that. I've seen customers manage to get 2.6-2.7TB on a 2.5TB LTO6 media when using hardware compression.

great explanation! thanks!