EMC Disks needed for SAP on Oracle

[Former Member]

HI All,

for a new SAP Global Rollout project we are planning to install a landscape (Dev, Tst, PrePRD and PRD) for ECC 6.0 EnhP4,

a landscape (Dev, Tst, PrePRD and PRD) for PI 7.1 and a landscape (Dev and PRD) for Solution Manager 7.0 (BPmon, Charm, Implementation, Service Desk, Test Management, System Monitoring). We have done a first sizing and we have need of about 80000 SAPS and about 8 TB overall. We are in contact with EMC and they have said that, as for SAP best practices, we need 300 disks to 148GB each. Have you some experience about the sizing with EMC? I think that 300 disks to 148GB are disproportionate.

Regards

Bob

[stefan_koehler]

Hello Bob,

at first i have to say that i have very bad experience with EMC storage systems, so maybe i am already prejudiced. We used a mid-range sub system (CLARiiON) some time ago and thank god we migrated to another storage system. All the following values are based on an IBM system based storage landscape (SVC + DS8700).

We have done a first sizing and we have need of about 80000 SAPS and about 8 TB overall

Well the SAPs is mostly used by CPU measurements .... to calculate the I/O subsystem you should calculate the I/Os per sec and the needed throughput. The needed I/O capacity also depends on factors like database cache, used databases features (like parallel query) and of course "tuned SQLs".

I think that 300 disks to 148GB are disproportionate.

Well .. that depends on how the I/O is spread over the "ranks", the speed (rpm) of each disk and many more.

for a Production system (ECC 6.0 ENHP4) of about 26000 SAPS, how many disk I/Os per second are necessary in your opinion?

Well as already said .. it depends on so many factors (like memory for database cache). I can give you some key data of our prod environment: 4 TB database, 4000 concurrent users, 50 GB database cache, round about 20.000 -25.000 I/Os per sec on SVC, 4 ms for single or multiblock I/O.

If your planned SAP systems are mission critical ones i really would double-check the suggested I/O subsystem. Mid-Range I/O subsystems really have their limits (especially in case of failures like service processors, etc.).

We are running on enterprise storage subsystems with virtual I/O layer and it's working very well.

Regards

Stefan

[Former Member]

Hello Stefan,

thank you very much for your collaboration. Let me give you some more details about our SAP implementation (a Global rollout programe). The main end-to-end processes in scope are: Plan_To_Produce, Order_To_Cash, Procure_to_Pay(purchasing), Procure_to_Pay(logistics), Management_Accounting,Financial_Accounting.

For all these end to end processes the SAP modules used will be: FI,CO,MM,QM,WM,SD,PS,PP,TR.

We will have max 1 TB database and 300 concurrent users. We donu2019t have any particular indications about database cache or used databases features (like parallel query) and tuned SQLs. Which are the typical values that we can consider?

Our SAP Production Systems will be two : SAP ECC 6.0 ENHP4 and SAP PI 7.1. Both of them will be on linux SUSE and Oracle. More probably we will have a sap four-landscape systems (DEV, TST, PrePRD and PRD). We have two other questions:

1) Are, in your lanscape, the SAP non-Production systems connected to the same storage system (50 GB database cache, round about 20.000 -25.000 I/Os per sec on SVC, 4 ms for single or multiblock I/O) of SAP Production systems? In other words are Production and non-Production systems connected to the same storage system? We think that connecting non-Production systems to a storage system with high performance characteristics, as it is for Production systems, is a real and big waste of money.

2) We think to use Vmware also for Production Systems but we have some doubts about the realization of an high availaility architecture. Infact if we use Vmware also for Oracle database how can we assure an high availability in the case of failure of an oracle service?

Thanks a lot for your precious help.

Bob

[stefan_koehler]

Hello Bob,

Which are the typical values that we can consider?

If i understand you correct, all these SAP systems will be new installations or not? If you already have existing systems that should be migrated you can check the physical reads per sec, reads per user calls, etc .. if these are new ones no need to worry at the beginning. 300 concurrent users are not that much on a new installation without any historical data.

1) Are, in your lanscape, the SAP non-Production systems connected to the same storage system

Yes - phyiscally all systems are stored on the same storage sub system (IBM DS 8700), but our high end productive systems are seperated by its own IBM SVC cluster (2 nodes) so that the caching functionality of SVC is reducing the (read) I/O load on the sub systems.

Well "waste of money" - what kind of I/O subsystem was suggested by EMC? I assume that it is not enterprise .. it's just mid-range for that landscape.

Both of them will be on linux SUSE and Oracle ... We think to use Vmware also for Production Systems

Ok - no problem, but be aware that the native MPIO driver of Linux (doesn't matter which distribution) has it's limits by spreading the I/O load overall adapters in simultaneous. Also please keep in mind that Oracle still can persist to recreate some issues on native hardware if you want to use VMware. You can bypass this limitation easily by using phyiscal raw disks in VMware and a dual-boot solution with linux. If you use VMware you also got the issue of the MPIO driver .. it's the same as using "native linux".

Regards

Stefan

[Former Member]

Hello Stefan,

we appreciate a lot your collaboration. EMC has proposed EMC CLARiiON CX4 240 (a midrange storage solution). We have a great doubt about the clusterization on VMWare. Infact we are thinking to use physical servers for Oracle Database+CI and Virtual(VMWare) Servers for Application Servers. In your opinion for the clusterization of Oracle 11.2 on SUSE 11 is it necessary a third-party software? Is the SAP native switchover solution efficient in your opinion?

Thank you very much

Bob

[stefan_koehler]

Hello Bob,

i am basically an oracle dba and we have migrated all of our non-SAP oracle database on VMware (with SLES 11 as VM Guest) this year and this is really no problem. The databases are running on an ESX cluster with 2 ESX hosts. You just need to think about the I/O load balancing when consolidating all I/O intensive applications (like oracle databases) and how you can work around possible support restrictions (by dual boot with Linux and physical raw disks).

The VMware Storage/SAN Compatibility Guide is located here: http://partnerweb.vmware.com/comp_guide/pdf/vi_san_guide.pdf

You will find the supported I/O policies for your EMC CLARiiON CX4 240 on page 98 - unfortunately you can't use Round Robin for your storage machine .. so you need to do the load balancing over all FC adapters manually.

Regards

Stefan

[Former Member]

Hello Stefan,

thank you for your feedback. Any experience or feedback about an heterogeneous cluster with two nodes one physical and one virtual?

Regards

Bob

[former_member376549]

Bob,

I work for the EMC sizing team and am surprised by the number and size of the disk this load was sized for. I just did a sizing for a similar load and we used 300GB drives and only 68 drives. It may be too late for you but I would be very interested in who did the sizing and the specifics to insure this never happens again. If you can supply any information to me I would be very appreciative. Hopefully it wasn't me that did the sizing but if so I can probably explain the reasoning.

With EMC Fully Automated Storage Tiering we can often greatly reduce SAS drives with just a few SSD drives while improving performance. Also do support production and non-production in the same mid-range frame for a large number of customers by using no SSD and 10K drives for test instances.

Also with EMC Vplex offers some potential for an active-active cluster for short distances.

Let me know the best way to get info on your sizing. It may have been a partner or a TC working outside corporate sizing team.

Thanks

Allan Stone

SAP Solutions Architect

EMC Solutions Design Center

[Former Member]

Dear All,

for a Production system (ECC 6.0 ENHP4) of about 26000 SAPS, how many disk I/Os per second are necessary in your opinion? Which are the typical disk I/Os per second that you have on your production systems?

Regards

Bob