Symantec Backup Exec

The left one is a LTO Ultrium 4 and the right one a LTO Ultrium 3 (my LTO3 tapes have a capacity of 391 GB, but your's are quite close to that figure). But that are only the media statistics not the capabilities of the tape drive. The HP Storage Works is a LTO-4 drive and the the DELL Powervault could be anything between LTO-4, LTO-5 and LTO-6 - see the library specs at the Dell website.

The restore rate is depending on the type of the data (small versus big files, docs versus databases etc.) and is depends which workload exists at the backup and restore servers. Did you try running the restore jobs after normal work hours or at the weekend?

even within weekend, the restore rate run as 113MB/min. Is that normal ?

This seems to be very slow. Do you have an Antivirus solution installed at the servers? Have a look at this Symantec Backup Exec Tuning article.

Also note that HP has a free utility called HP Library and Tape Tools.  One of the things you can use it for is to simulate backup or restore jobs to help identify performance bottlenecks.

Download the utility from http://h18004.www1.hp.com/products/storageworks/ltt/index.html.
You can model a restore session in the tool.

If you're experiencing performance issues, I also recommend you make sure that your tape drives and libraries have the latest firmware.  L&TT can do this for your HP gear.

Can you describe or diagram your backup infrastructure?  That is, how are the tape drives connected to the servers?   What operating systems are involved?   What are you backing up (type of data, size of files, etc.)?   Is performance different when you run a job on drive A, versus drive B?

Well restores are always slower than backups, but that does look a bit slow.

Mind you, your backups are not too speedy either 2.1GB/min is only 36MB/sec less than half what the drive is capable of, and only just above the minimum speed before it starts shoe-shining.

Maybe the minimum speed is why the restores are so slow?

NAV has been disabled but it doesnt' help.
2.1GB/min is less than half waht the drive is capable. Where can you tell this ? Is this the speed rate for LTO-4 tape ?


The Backup Exec media server is installed on Window 2008 R2 SP1 that is connected to HP StorageWorks 1/8 G2. The server will backup its local drives and few more servers through the agents.

We are building a tapes and it reads for 934Gb, with Job rate 133 MB/min. The Elasped Time is 111:34:42 and it hasnt' finished yet.

The tape statistic is
Used :590Gb
Available : 190Gb
Written : 900Gb
Read : 120Gb
Compression ration :  1.45:1

Any idea to try tunning the performance is appreciate ? In addiiton, how much data will it read as the tape only used 590Gb ? Tks

LTO-4 has a native speed of 120MB/second -- 7,200 MB/minute, or over 400GB/hour.
If your data compresses at 1.45:1, it's full-speed writes will be at
174MB/sec, 10,440MB/minute, or 626GB/hour

LTO-4 tape cartridges are native 800GB.  You should be able to fit about  1.1TB of 1.45:1 compressible data on a single LTO-4 tape.

As slow as you are feeding the drive, I'd recommend you turn compression off -- you'll use more tape, but you'll stream more, and your tapes and tape drives will last much longer because they won't be continually stopping, rewinding and starting again as the buffer continually gets empty.

The first step in investigating performance issues of tape drives is to get on the latest rev of firmware for both the drive and the library/autoloader.  HP's free Library and Tape Tools (see post above) will do that for you simply.

Here is a summary of HP LTO drives

From HP QuickSpecs
          Cap	                        HP Speed     HP Data Rate Matching
LTO-1	100GB			        16MB/s	0-16MB/s
LTO-2	200GB			        24MB/s	0-24MB/s
LTO-2	200GB	Ultrium 448	HH	24MB/s	0-24MB/s
LTO-3	400GB	Ultrium 920	HH	60MB/s	20-60MB/s
LTO-3	400GB	Ultrium 960		80MB/s	27-80MB/s
LTO-4	800GB	Ultrium 1760	HH	80MB/s	33-80MB/s
LTO-4	800GB	Ultrium 1840		120MB/s	40-120MB/s
LTO-5	1500GB	Ultrium 3000	HH	140MB/s	47-140MB/s
LTO-5	1500GB	Ultrium 3280		140MB/s	47-140MB/s

LTO-6	3200GB			        210MB/s

Select allOpen in new window

Media durability 1,000,000 passes on any area of tape,
equates to over 20,000 end-to-end passes/260 full tape backups

@rjanowsky - disagree that you cannot hit the tape speeds specified, if you feed the drive data fast enough it WILL do those speeds!

The problem is getting the data off disk fast enough to feed the drive not that the drives can't do it.

The figures in my previous post are for uncompressed data on tape, so with compression the drives will accept data even faster.

We are building a tapes and it reads for 934Gb, with Job rate 133 MB/min. The Elasped Time is 111:34:42 and it hasnt' finished yet.

The tape statistic is
Used :590Gb
Available : 190Gb
Written : 900Gb
Read : 120Gb
Compression ration :  1.45:1

Any idea to try tunning the performance is appreciate ? In addiiton, how much data will it read as the tape only used 590Gb ? Tks

At 133MB/min, thats 2.2MB/sec it sounds like the drive is shoe-shining, ie you are not feeding the drive fast enough. The LTO-4 needs at least 33MB/s to hit streaming speed

Install the HP LTT and stop all the BackupExec service. Run the diagnosis but it tells that the device is busy.

However, I can't find any option about testing the tape device read/write speed. Does that provide this function ?

Actually, I still can't sort out the bottleneck (hdds or tape device) ?

Tks

Yes, you can test the tape read/write performance.   See the icon "Dev Perf" just two over from the big yellow help question mark (or from the menu, "Function" --> "Device Performance").  This will allow you to read from or write to the tape drive directly to/from memory.

If you want to test your hard drive read/write performance, use the "Sys Perf" icon, which lets you create a test data set customized to your needs, and then performs the indicated disk <--> memory reads or writes.

In my experience, it is rare that the tape drive is the bottleneck.  The Windows file system, and how backup applications have to access it, generates abhorrant performance.   The preponderance of  small and tiny files, the deeply nested directory structures, fragmentation, and long file/directory names all contribute.

Thanks. Does it mean that by comparing the result from "Sys Perf" to "Dev Perf", I need tell the bottleneck ?

Why it always say my device is busy ? I have stop all the Backup Exec service. Do I need to reboot the server ?

Based on the posting above,
LTO-4      800GB      Ultrium 1760      HH      80MB/s      33-80MB/s

My current backup rate is around 2,162 MB/min -> 36MB/s. Based on this result, the tape device should be fine for backup. Can we assume that the hardware is fine and should I focus on restoring, (Window, file system, SQL express come with BackupExec...)



Tks

It can't recognize the tape driver. Any idea ?
HP-Tape-drive.bmp