D2D Backup System Vs Tape Backup Vs Standard Disk Backup

[mohannad]

Hi All,

My backup is taking too long over LTO-5 FC, im trying to reduce the window will HP D2D help ??

ive read in some forms that it takes more time when dedup is used !!

Do i have any other option for disk based backup either than the D2D system ??

Regards,
Mohannad

P.S. This thread has been moved from Tape Libraries and Drives to Disk-Based Backup. - Hp forum Moderator

[Sudhakar Subramaniam]

You can always use HP VLS.

http://h10010.www1.hp.com/wwpc/us/en/sm/WF04a/12169-304616-1153414-1153414-1153414.html

[Richard Bickers]

The LTO 5 is a very fast drive so the first thing I'd check is if you're actually getting data to it fast enough. It's often the source data that is the bottleneck and that determines the backup window - in which case it doesn't matter what device you have at the other end.

My suggestion is to use the LTT diagnostic (http://www.hp.com/support/tapetools ) and run the system performance backup pre-test to measure how fast your source data can be accessed. If that's not as fast as the drive can accept it (~240MB/S at 2:1) then that's where your bottleneck is.

Of course, if you can source your data at over 240MB/S then you probably need something more substantial than a single tape drive to receive it.

You could also pull a support ticket after your backup is complete and that will tell you how much data, what data rates and what compression ratios you are getting.

Post the ticket here and we'll take a look.

[mohannad]

Hi Richard,

the main point in this thread is to differentiate between D2D solutions and Standard D2T solutions in terms of throughput, i donâ t have any problems in my tape device and i am getting the maximum through put of itp; no help is needed here.

Every sales guy I had is telling me D2D is supposed to be faster than D2T but i cant see that when the maximum through put of the a D2D system is 2.4 TB, and 2 TB per tape drive which makes my MSL 6060 4 times any available D2D

[mohannad]

Hi Sudhakar,

partially, because not all the VLS systems have increased through-put over the tape devices and when thats true the costs are sky high, i hoped that the D2D might be a considrable solution but looks like its not.

Thanks,

[Richard Bickers]

I've had a chat with the D2D performance guy and there are two important keys to performance:
1) A single stream (to a single virtual tape drive) is limited to about 250MB/S. You can go much higher than that if you use multiple streams as long as...
2) The de-dup kicks in which reduces the need for internal disk writes and your overall throughput can go up.

Your first backup to D2D will be about the same as to a single tape drive. After that, it should increase as duplicate data can be skipped over. You'll need to use multiple streams to get the most out of it.

Obviously the amount of 'de-duping' you get will depend on your data.

[Víctor Cespón]

As stated above, a LTO5 is a very fast drive, the server must have a very fast disk subystem to feed it at full speed all the time.
The idea behind D2D backup is that you can define many drives and have more backups running in parallel. You can have one drive for each server, or even for each backup job, so you can be copying one F:\ to one virtual drive and G:\ to another one.

A VLS can handle many hundreds of MB/s, depending on the number of disks it has.

[Michael A. McKenney]

I run two LTO-4 tape drives. I am considering a two more tape drives to speed up backups. I split the servers up between the two drives. I can backup in 5.5 Hours due to connectivity of 3 of the servers.

My concern about D2D and Deduplication is not having a backup off site. My CFO wanted to do off-site D2D. With 900 GB of data, I recommadned a Active to Active off-site SAN solution instead. You will want to do a full backup off-site a few times a year. Across a T1, 900GB was 55 days.

[Dave Dewar]

As Richard has stated, the D2D really does well when multiple streams are sent to it in parallel. If you want to maixmimse performance you need to run it in this way and you will not acheive headline performance with 1 or just a few parallel streams.

Michael, D2D replication would work well for keeping remote copies of backups. Once the initial seeding backup is done from source to target then only the chanegs from one backup to the next would be sent across your low bandwidth replication link.

There is a D2D performance best practices document at http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02511912/c02511912.pdf

that discusses how to configure a D2D for best performance and some of the factors to be aware of. There is also content there for replication and many other elements

Cheers,

Dave Dewar

[mohannad]

Hi Richard,

Sorry ive been away for the past few days, actually during my trip ive seen a HP presales and hs official response was that D2D is not compared to tape in terms of speed becuse there isnt that enhancment in the performance.

But what you said is intresting i never did think about multi-streaming to the D2D,since in normal busnsise practice due to source issues you can never achive tape maximum throughput; using D2D multi-streaming will difenitly help in the process.

But im wondering

1-How many parallel streams can i run at once.
2-when deduplication kicks in its going to decrease the performance so in avarage whats the maximum throuhput that i should excpect from the D2D system

[Richard Bickers · Accepted solution]

The performance document that Dave refers to is pretty good and a quick look at that (Upstream and Backup Application considerations on page 8) shows a graph with up to 16 streams but the sweet spot seems to be at about 6. That's the point at which the deduplication becomes the bottleneck. The example given is with the D2D4009i giving 40MB/s from a single stream getting up to about 90MB/s with multiple (presumably 6+) streams.

Not as fast as tape for sure but there are a number of other advantages with a D2D solution that make it a good bet. Nothing wrong with tape backup - it's just not as fashionable these days!

[mohannad]

Im starting to get the idea that D2D may be a better replacment for a tape library in terms of through-put compared to traditional tape devices.

Itâ s not about maximum throughput of D2D vs. TL, itâ s because TL mostly will not operate in maximum throughput due to source through-put; basically the Multi-streaming should help in this regards.

What remains now is the input of someone who actually replaced a TL with a D2D, did he find this to be true?

i will be most appreciating if anybody can reply to this point