StoreEver Tape Storage
cancel
Showing results for 
Search instead for 
Did you mean: 

SAN backups performance

SOLVED
Go to solution
Lonie Waller
Advisor

SAN backups performance

Hello all,
Looking for some help. I am running DP 5.1 Cell HP-UX 11i 2 HBA connected to McData Switches zoned to see the Adic i2000 LTO3. I am only getting about 100gig per hour. Same as my network backups I am missing something. Help appreciated.

Thanks
17 REPLIES
Richard Bickers
Trusted Contributor

Re: SAN backups performance

You can verify that the bottleneck is with sourcing the data rather than with the tape drive or library using HP LTT free download diagnostic from www.hp.com/support/tapetools.

Just select the system performance tab and try it out. That will tell you what data rates your are getting from your disks and therefore the maximum you can back up.

If you suspect the drive (which is less likely) then you can use the device performance tab and try writing test data to a tape. That will tell you the performance of the server, HBA, driver, cabling and drive/media - which ought to be 80MB/S+ (300 GB/hr) for an LTO3.
It's more interesting when it's gone wrong
Alzhy
Honored Contributor

Re: SAN backups performance

How many drives are actually engaged when you observed that 100GB/hour thorughput?

Also:

Are you sure you are feeding your backup system enough data to fully utilize the drives? i.e. it is possible you are streaming 4 save streams (filesystems/paths) to just 1 LTO drive inside your ADIC... or if you onlyhave 1 LTO drive - then 100GB / hour is pretty decent already.

HTH.
Hakuna Matata.
Lonie Waller
Advisor

Re: SAN backups performance

I will try out the tools.

I am running 1 drive in this test backup. Tried mulitple file systems and one file systems range from 50 to 400 gig being backed up. I ran a backup over the network and got 138gig an hour to one drive. SAN should be faster then LAN in my opion.

Thanks for the info.
Alzhy
Honored Contributor

Re: SAN backups performance

Lonie,
Peace and Clean Air/Earth.

Can you elaborate how you did your network based backup please? You mentioned you were able to get better network backup throughput than your SAN(locally) based backup to your LTO. Was your network backup from disks - to your desitnation backup server and on to your LTO3 drive on your backup server? Or is it to a disk on another server?

IIRC, LTO3 has an average throughput (uncompressed) of about 30 MB/sec -- which should be around 108GB/hour assuming everything is perfect.. This closely matches your observed throughput of 100GB / hour. So I think you do not have a problem. Also have you checked if your backup software has compression enabled (bot onthe software and in the hardware)? -- This can additionally bump up your throughput in some cases.


Hakuna Matata.
Lonie Waller
Advisor

Re: SAN backups performance

Ok this is my setup for backups.

Data Protector 5.1 cell manager (Zeus) is HP-UX 11i L1000, 2 HBA 2gig A6795A to McData switch. I am using Adic i2000 with 3 LTO 3 drives Fiber to McData switch. Zoned so Zeus can see drives and robotics. Backup that I got 138gig hour was a different server called Sally using Zeus's drives. Sally's disk is fiber attached SAN disk. It backed up about 150gig.

Also LTO 2 is closer to 30mb/sec. LTO3 is more closer to 80mb/sec. Native.

For network base backups my through put is very good. but I should not be getting the same through put for SAN backups am I missing something?

Thanks for you info
Lonie Waller
Advisor

Re: SAN backups performance

Also that last reply was my setup for Network based backups.

I set up another server Dudley through the SAN zoned for the Adic i2000 same as I did for Zeus. So this is using it own devices going over the SAN to backup its fiber attached devices through put same as network or little worse.
Alzhy
Honored Contributor

Re: SAN backups performance

Ah I see now.. So Zeus is your backup server. Sally and Dudley are your "SAN Backup clients" (for lack of a better word as I do not have DP experience.. only NBU, Networker, BrightStor and TSM).. And you're saying Dudley and Sally backs up better as network clients than as backup clients.

Well I think that is still normal... via network your only overhead is network (if it's a pure GigE link to your backup server - you can have throughputs of as high as 60-70 Mbytes/sec. -- IF sally and dudley's filesystems can support it). On Zeus - it probably is using compression both on software and the drive so it can possibly push the stream better to the LTO device -- or possibly using/streaming to more than one LTO drive.


When you backup Sally and Dudley locally (SAN based) - are their HBAs common for both the disks and the LTO drive(s)? If it is - then I can already see that overhead.. The same HBA being used to suck data out of your disks and the same HBA used to push it to tape. Our SAN backup architecture is such that our robots and library have their own SAN and their own HBA(s)...

Hakuna Matata.
Lonie Waller
Advisor

Re: SAN backups performance

I have dedicated HBA's for the backups so not contention there. I am not a network guy but its not a private network for the backups so I would think there would be some hiccups over the LAN. ALso forgot to mention Zeus the cell has two gig nics using AUTOPORT.

I would just think that a server connected to a SAN and library connected to a SAN basically local connection would get alot better though put.

Past experience I used a MSL6060 LTO2 drives over the SAN getting close to 220 gig an hour. I expect at least that from LTO3.
Alzhy
Honored Contributor

Re: SAN backups performance

Then I guess the next steps in your case can be:

1.) Check your SAN configuration for errors or configuration efficiencies.

2.) Get HP's help

3.) Get ADIC's help

4.) Get HP and ADIC together if you can.

Hakuna Matata.
Lonie Waller
Advisor

Re: SAN backups performance

Thanks for you help.

Lonie Waller
Advisor

Re: SAN backups performance

Has any one heard that LTO 3 drives are not performing as well as expected because the physical hard drives can't feed them the data fast enough?
Alzhy
Honored Contributor

Re: SAN backups performance

Yes.. it is farily common and may be a glaring possiblity in your case.

IF you are sucking data out individual Filesystems - the more so.

Have you tried streaming several filesystems to a lone LTO3?

Filesystems (VxFS) on SAN Arrays and 2G FC-HBA and DirectIO or Discovered DirectIO can give you anywhere between 50-60 Mbyte/sec. but may vary depending on what (and how big) files are on the filesystem. Reading vai its RAW device can get you close to the theorethical speed of your FC for certain volume configurations.

Try doing:

dd if=/dev/vgxx/rlvolxx of=/dev/rmt/Xm bs=nn

to test your LTO Trhoughput...

Hakuna Matata.
Lonie Waller
Advisor

Re: SAN backups performance

Thanks I will give that try
Lonie Waller
Advisor

Re: SAN backups performance

No fimilar with the dd but it keeps giving me /dev/rmt/1m: I/O error
dd: cannot create /dev/rmt/1m

any thoughts?
Alzhy
Honored Contributor

Re: SAN backups performance

Whatever device (/dev/rmt/Xxx) does DP use? Use that.

or you can find out via:

ioscan -kfnC tape

Am not familiar what device modifier to use though if it is /dev/rmt/Nm.

Of course .. be sure you have a test tape mounted i.e. via the "mc" command it it supports your ADIC..
Hakuna Matata.
Lonie Waller
Advisor

Re: SAN backups performance

This is the on DP uses

dev/rmt/1m
Alzhy
Honored Contributor
Solution

Re: SAN backups performance

You need to be root..
You need to have a tape mounted.
DO an ioscan -kfnC tape..
Hakuna Matata.