Re: Speeding up RMAN backup using TDP
Date: Fri, 9 Jul 2010 14:15:58 +0200
Message-ID: <AANLkTin9k5ygBz6iTBNLjcnxpQ-cg9nCKn-JU0P6Qfss_at_mail.gmail.com>
I've identified some things... despiting some problems network related ... I'm able to see that
- Max I/O for a single datafile is about 15MB/s per channel, allocating 4 channels I can reach about 80MB/s in reading
- Previous backup was done using BMC SQL Backtrack that permits to have a 76% of compression and use 'BACKUP AS COPY INCREMENTAL LEVEL = 0'
So I'm sure that BMC SQLBacktrack takes less time to backup as with a better compression level has less data to send to TSM Is not clear why using a single channel I can't reach the same reading performance as four channels... This seems not related to network or local I/O... may TSM be limited in incoming bandwidth?
Ste
On 9 July 2010 12:50, ~Jeff~ <jifjif_at_gmail.com> wrote:
> Hi Stefano
>
> It looks like your I/O performance is very low(~75GB/hr with SQL
> backtrack), I'd suggest looking into that first - perhaps by seeing if a
> disk-to-disk copy can do any faster to help identify where the problem is.
>
> For comparison, our HPUX Itanium servers with EMC SAN and RAID-5 can copy
> disk-to-disk at about 300GB/hr. At a previous site, a full level-0 RMAN
> backup could do either 3 or 5 TB (don't have my notes on hand!) in 10 hrs -
> this was Sunfire server with a dedicated Gb-ethernet LAN for backups going
> to TDP with disk pool staging and around 6 tape heads. The TDP server had
> heavy contention for resources from other databases though.
>
> But I'd suggest finding if/where the I/O bottleneck is before bringing
> RMAN into the picture.
>
> There is also a very good Oracle whitepaper on tuning RMAN which helped me
> to halve level-0 backup times.
>
> Hope that helps...
> Jeff Wong
>
>
> On 3 July 2010 07:34, Stefano Cislaghi <s.cislaghi_at_gmail.com> wrote:
>
>> Hello all,
>>
>> looking here for some tips on debug RMAN backup using TDP.
>> Simply my RMAN backup is working, but is slow.
>>
>> My enviroment is using a TSM server that uses disks and not tape...this
>> should be quite fast.
>>
>> Actually we're using a third party tool (BMC SQL Backtrack) to backup and
>> this is doing for comparison 100Gb of DB in about 1h30m.
>>
>> My RMAN full backup using TDP for same 100Gb takes 3h.
>>
>> There's no RATE defined and restrictions on RMAN channel instantiation and
>> in dsm.opt for TDP.
>>
>> Simply looking during backup my disks reading does not reach a speed up to
>> 20MB/s.
>>
>>
>> Any suggestions?
>> Thanks
>> Ste
>>
>
>
-- http://www.stefanocislaghi.eu -- http://www.freelists.org/webpage/oracle-lReceived on Fri Jul 09 2010 - 07:15:58 CDT