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backup can take more than optimal time

SybDBA
Participant
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Dear All,

In what cases a backup can take more than optimal time??

I am unbiased in this situation that, Is it related to IQ or any OS level settings affecting the backup time?


during the backup any connection can affect the backup time?

suggestions and pointers will be appreciated.

regards,

Vivek

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Answers (1)

Answers (1)

markmumy
Advisor
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Vivek,

There are no real settings in IQ to help speed performance.  Most of the time IQ backup performance is really related to the host system and storage.  To illustrate the issue, take a scenario I had with a customer some years ago.  They had a 20 TB IQ database that needed to be backed up.  The business required that the backup took just 2 hours.  That's about 10 TB/hour from disk to tape.  The tape infrastructure, though, could only handle 1 TB per hour per tape drive.  The first order of business was to politely point out that, outside of IQ, the tape library system would need a 10x increase in capacity to handle their requirement.  See IQ was immaterial to the discussion as it could have been ASE, Oracle, or even a filesystem that needed to be backed up.

Next was just reading the data from disk.  Again, outside of IQ to read 10 TB/hour you need storage that can read data at nearly 3 GB/sec (3GB * 3600 seconds = 10 TB/hour).

Lastly, the data had to be moved across the network.  As with storage, the network needed to support 3 GB/sec or 24 gigabit.  That required an increase to 3 10 gbit ethernet links dedicated from the host to the tape library.

So now we had the infrastructure properly increased to handle the 10 TB/hour rate (3GB/sec).  From there we simply started an IQ backup with enough parallel streams to copy the raw devices direct to tape.

How large is the database?  What time frame do you have to back it up?  Will it be going to tape or direct to disk?  If you could stream the IQ devices direct to the backup without needed to use the BACKUP statement would that work?

Mark

SybDBA
Participant
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Hi Mark,

Thanks for promptness...!!

required details i have provided below for the reference

1.Database size is about 5TB.

2.Generally it takes 7-8 Hrs.(Backup schedule time is around 12PM in the day without any connections, but this time it took 11Hrs. for the same data.)

3.Backup is direct to disk.

Sorry but, I ahven't got the point above you have mentioned,

'  If you could stream the IQ devices direct to the backup without needed to use the BACKUP statement would that work? '

We are using the BACKUP statement inside cron job to schedule the backup with 15 stripes.

Regards,

Vivek

markmumy
Advisor
Advisor
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My question was around whether or not you could use something like storage replication rather than an IQ BACKUP command.  With storage replication we can have the database safeguarded much quicker.

For a 5TB database, though, you should be able to back it up to filesystem much faster than 7-8 hours (or 11 hours as you saw recently).A rate of 1-2 TB per hour from IQ to filesystems is quite possible.  As I mentioned in my original post, though, performance is nearly always related to hardware performance. 

The key thing is to make sure that you have enough IO bandwidth to write data to filesystem (bypassing cache) in a rate that gives you the desired throughput.  The same can be said when reading the IQ devices.  So long as you make sure that you have proper hardware, you can achieve your desired backup metric.  It may require multiple filesystems or an increased IO footprint for IQ, so please keep that in mind.

Mark

SybDBA
Participant
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Hi Mark,

As you said that enough IO bandwidth and proper hardware can make it optimal, i ask this issue to a storage team guy and he suggested me the same.

Only the shocking thing which had happened with me that I am backing up this particular server(database), hence I was quite surprised when it has taken much time than a regular backup time.

Despite of these all happenings, the business team didn't took burden to take further this issue, then i also didn't shown any interest. because this will impact them not me.

As i am a database person there is no more authority to me that investigate this, just let him know how much time it took than previous.

Thanks a lot for your inputs on this issue...!!

Regards,

Vivek