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Restore Takes long time

 
Mahmoud_1
Frequent Advisor

Restore Takes long time

Dear All,
I have two SDLT Tapes attached to two Alpha Servers ES45 clustered on HSG80, Running OpenVMS 7.3-2 and Oracle RAC 9.2.0.5 .
Problem is when a failure occurred we need more than 20 hours to restore 100gb.
Note the disks formatted as ODS-5.
I tried to restore the data on another system with disks formated as ODS-2 it takes only 3 hours.
Oracle is not my responsibility in this site.

Any OpenVMS suggestions will be appreciated.
Regards
16 REPLIES
Marc Van den Broeck
Trusted Contributor

Re: Restore Takes long time

Mahmoud,

I have done some testing with ods-2 and ods-5 and found no difference in speed while copying files.
But, I found differnces between a mirror set and a raid-5. Copying to the raid-5 took 2 times longer.
So, can you check whether you are using mirrored discs are raid?
But even then a factor of almost 7 has to have another cause. Or you using the same tape device?

Rgds
Marc
Mahmoud_1
Frequent Advisor

Re: Restore Takes long time

OK Van,
I have Data on raid-5 and raid-1.
I have same case on singl Systems (DS25,ES40,ES45) with no raid.
Regards.
Wim Van den Wyngaert
Honored Contributor

Re: Restore Takes long time

Are there FDDI shadow disks (or other slow connections ? What tape drive did you use in both tests ? What process quotas for the users that did the test ?

Wim
Wim
Volker Halle
Honored Contributor

Re: Restore Takes long time

Mahmoud,

in general, performance problems are hard to discuss and speculate about in a forum like this.

As you can see from the questions raised already, you need to provide a lot of data and details about your performance problem, if you expect more than just more questions and speculation.

You need to describe:

- the command(s) used
- the HW config involved (down to the disk/tape layer)

Volker.
Jan van den Ende
Honored Contributor

Re: Restore Takes long time

Mahmood,

Do the ODS-5 disks have High-watermarking enabled?
It _IS_ the default, and so easily overlooked.
That WOULD explain slowdown of this magnitude.

If yes, do you REALLY need it?
$ SET DEVICE xxx/NOHIGH will help here.

Worth checking...

Proost.

Have one on me.

jpe
Don't rust yours pelled jacker to fine doll missed aches.
Mahmoud_1
Frequent Advisor

Re: Restore Takes long time

Dear All,
In fact I dont have shadow disks or volumes.
About the backup command its simple:
$backup/log/image/ignore=(inter,nobackup) $1$dga30: mkb500:disk3.bck
and the restore its the same.

Regards.
Wim Van den Wyngaert
Honored Contributor

Re: Restore Takes long time

As Volker said, we are missing a lot of data.
Also on controller level there are settings that can influence performance.

Wim
Wim
Mahmoud_1
Frequent Advisor

Re: Restore Takes long time

Thanks all for fast response,
I will returne to the site HW Engineer for more information about the HW configuration.
Regards.
Mahmoud_1
Frequent Advisor

Re: Restore Takes long time

Hi to All,
H/W enginer sent me the Tape specifications:
KZPBA-CA SE SCSI Controller
HP SDLT 160/320GB Tape Drive

Best Regards.
Antoniov.
Honored Contributor

Re: Restore Takes long time

Hi Mahmoud,
I'm not sure KZPBA-CA SE can run Ultra Wide3 SCSI (160Mbs); it appear as Ultra Wide (40Mbs) that's 4 times slower than your tape driver.

Antonio Vigliotti

Antonio Maria Vigliotti
Antoniov.
Honored Contributor

Re: Restore Takes long time

For for example,
you can see in island page http://www.islandco.com/scsi.html
KZPBA-CA is not ultra160 like IC-KZPEA-DB or 3X-KZPEA-DB

Antonio Vigliotti
Antonio Maria Vigliotti
Veli Körkkö
Trusted Contributor

Re: Restore Takes long time

how about adding

/BLOCKSIZE=61440

to your backup command. It might make the backups pretty much faster and will also help restores.

_veli
comarow
Trusted Contributor

Re: Restore Takes long time

There is a real problem is cache on SAN devices. It thrashes. Try reducing the diolm to 32. Note that xwindows won't start.
comarow
Trusted Contributor

Re: Restore Takes long time

I'll add that if you must use xwindows the min is 100, but if you can do it in batch keep diolm below 32 even as low as 4 to prevent the san from thrashing.
Mahmoud_1
Frequent Advisor

Re: Restore Takes long time

Hi,
In fact I passed all information to my customer site engineer, I am waiting.
I will Assigne points regarding to the solution.
.
Dear Comarow,
I want to inform you that the problem as i mentioned is on both SAN and local disks attached on single machine.

Best Regards.
Emad Omar
Regular Advisor

Re: Restore Takes long time

Dear all,

Thank you for your kind replies. But I need to clear something which it is very imporatnt to all of you. SDLT 160/320 Tape Drive has an Ultra 2 SCSI LVD Interface. This means that speed of the I/O will not exceed more than 80 MB/s even used Ultra 3 SCSI Controller. Therefore the Ultra 2 SCSI Controller (KZPCA-AA) is a good choice for using these SDLT Tape Drives on Alpha Servers.

On other hand I noticed that this problem was appeared at SAN/Cluster environment and also at Single Servers. So thinking on SAN configuration is putting aside.