Slow backup on disk and tape?

[Carlton_Whitmor]

I'm running an LTO-2 external tape drive (Certance Iltrium 2), on a Dell PowerEdge 2550 (dual processor and 4GB Memory) running Windows 2003. Whether I do a backup to disk or tape I'm only getting about 200MB/min speeds.

Here is what I've done so far:

Set NIC and Switch to be 100MB FullDuplex

Ran Updates for BE 10d and Server Agents (Rebooted)

Defragmented Drives on Media Server

Updated BroadComm GB NIC driver

I did a search on this and found a suggestion of copying large files to and from this server. Is there a speed utility I can run to find out how fast the files are copying from one server to the media server?

Any other suggestions?

[Ken_Putnam]

You can do it wih a little CMD file

Create a file called CR.TXT.   in this file put only a carriage return

then your cmd file would look something like this

TIME < CR.TXT

XCOPY  \\Server1\Share1\dir\file.ext    \\Server2\shre2\dir\

TIME < CR.TXT

this should display the system time to the hundreths of a second, copy the data then display the time again

[Carlton_Whitmor]

Ken,

Thanks for the info. Looks like there is something going on with BE 10d. When I do a backup of data that is local to the media server I also get slow throughput at 160MB/min. This server is a PowerEdge 2550 with Perc SCSI controllers.

Any idea what I can do to speed this up?

[Ken_Putnam]

From teh devices tab, right click the tape drive\properties

what is listed for block size, buffer size, number of buffers

Also the settings for Pass through and Single Block

(is this a locally attached tape drive?)

[Carlton_Whitmor]

Ken,

Here are the properties below. The tape drive (Dell LTO-2) is attached locally, but is external on the Adaptec 39160.

Block size = 64k

Buffer size = 64k

Buffer count = 10

Read single block mode = off

Write single block mode = on

Read SCSI Pass-through mode = off

Write SCSI Pass-through mode = on

[Ken_Putnam]

Write single block mode = on

That's your problem.  with this turned on, BackupExec totally bypasses  buffering.  it will read one block, write one block, read one block etc.

Also, Symantec recommends that the Pass throught options only be enabled for SSO devices (see the Admin Guide)

Personally, I'd set the buffer to 128K or 256Km but leave the buffer count at 10

[Carlton_Whitmor]

Ken,

Thanks for the advice on the tape device settings. I will make those changes before my weekend backup. What about the D2D settings?

They don't offer much in the way of configuration. Here is how it's set now:

Maximum size for Backup-to-Disk files: 20GB

Maximum number of backup sets per Backup-to-Disk file: 300

Disk Space Reserve: 10GB

Auto Detect Settings = On (Buffered Reads and Buffered Writes are grayed out)

Allow (1) concurrent operations for this Backup-to-Disk Folder

Carlton.

[Ken_Putnam]

I'd set the Max Size lower 1 GB perhaps.  If your job backs up 20.01 GB, you've used 40 GB of disk space

Also remember to keep your B2D volume defragged.  Fragmentation can REALLY slow down B2D writes

[Carlton_Whitmor]

Ken,

Thanks for your help.

[Ken_Putnam]

One more thing to bear in mind

with a 10GB reserve, when the free space on the volume falls  below 10GB, BackupExec will nolonger create new BKF files, so if you have anything else using space on this volume, keep a close eye on it

[Carlton_Whitmor]

If I have the D2D drive set to "Append, Overwrite if n appendable media is available" won't it overwrite when it gets down to 10GB?

If not, is there no way to do that?

[Ken_Putnam]

The problem with Append is that Backup Exec treats every BKF file created that way as part of the original "multi-volume backup set", and when each backup  closes, the OPP is reset. As such NONE of the BKF files will ever be overwritten,  because the OPP is xxx days as of the last completed job

Usually Append is used in conjuction with an Overwrite job.  Say a Weekly Overwrite and daily Append

This way, when the final (fourth) daily writes to it, the OPP is never reset again   You still need to specify the same media set for the two jobs, since APP and OPP are by media set, not by tape volume or job name

[Jeffrey_Funnell]

I am running a Poweredge 2800 with a SAS array attached to it.  I am using the SAS array for all of my disk-based backups.  I am getting extremly slow speeds on both disk and tape backups.  For the tapes, I am getting about 800Mb/min and the disk I am getting about 100Mb/min.  I have tried several of your suggestions but none of them worked.  If I backup anything off of the SAS array using tape, I get awsome speeds about 3000Mb to 5000Mb/min.

Any suggestions??

Thanks.

[bjash]

What RAID level is your SAS array at?  Some RAID levels offer better read performance than write performance.

[Ken_Putnam]

@jeffrey

If your disk array is RAID5, write performance can be fairly slow, while  read will  be much faster

[Jeffrey_Funnell]

Ok thanks.  I will look into which level of RAID we are using and see if we can possibly fix that.  Any ideas as to why I am getting extremly slow speeds when writing to tape?  The data that I am backing up to tape on a weekly basis is not coming from the SAS array but from the main system.

Thanks.

[bjash]

Some items that I have had in the past with write speeds have sometimes been from factors such as:

Driver for tape drive (update)
Driver for controller connected to tape drive
Firmware for controller connected to tape drive
BIOS on server board
Chipset driver (if applicable)
Faulty cable from controller to tape drive
Clean tape drive or faulty head on tape drive

One way to rule out BE as a problem is to do a test backup with NTBackup and see if the write speed is faster--this would point you in the right direction--if it was a backup software vs. hardware/driver issue.

[Ken_Putnam]

some have reported no difference, but from the Devices Tab, right click the drive\Properties

what are the settings for

Block Size, Buffer Size, number of buffers, both Single Block. options

Block size should be as large as the device will support (64K, 32K, etc)
buffersize  at least twice the block size, I usually go with 512K
number of buffers default is normally OK

both Single block options should be DIS abled