SAP Installation on Oracle and Linux

[Former Member]

Hi,

We are planning to implement SAP ERP along with other products like BI, BOBJ, SRM, Portal and PO on Oracle 12 and RHEL7 environment and our server requirement is-

1) Almost 120000 SAPS

2) 30 TB usable storage.

3) VMware for all systems

Different Hardware OEMs have proposed different architecture related to IOPS and CPU and I have few doubts on IOPS as OEMs have proposed mix architecture of SSD, SAS and NL SAS disks, (Production will have SSD and SAS only).

1) How the filesystem should be design as per storage specific like Production file systems on RAID 10 and DEV and QAS on RAID 5 or 6.

2) Some vendors has proposed SSD for cache and licensing for auto tearing in which hot data will automatically move to SSD for better IOPS from SAS disks.

3) Some vendors has proposed SSD for some file system too in PRD environment like for BW and BOBJ as they need high IOPS and redolog file system too (origlog and mirrlog).

What is standard best practice, we are considering 20% SSD to meet our IOPS requirement as per SAPS calculation, We don't want to install systems on pure SSD disks as we can get the required IOPS from 20%SSD and remaining SAS drives.

We are also planning to implement D2D backup and then tape out and wants to keep 1 day backup on disk.

a) Shall we consider SSD only for caching or for filesystem too ??

b) What all filesystem we should plan on SSD ??

c) What different architecture we should consider for ERP (OLTP) and BW (OLAP) ?

d) What should be RAID design for PRD and non PRD environment ??

Saurabh Mishra

[stefan_koehler]

Hi Saurabh,

> 3) Some vendors has proposed SSD for some file system too in PRD environment like for BW and BOBJ as they need high IOPS and redolog file system too (origlog and mirrlog).

Have they really proposed SSDs for redo or have they talked about cache and SSDs (e.g. like EMC Symmetrix) or have they talked about a flash array? If they really proposed the first one - then remove these vendors from your list immediately. Just google "Oracle SSD redo".

> a) Shall we consider SSD only for caching or for filesystem too ??

Depends on the SLAs, the load profile, storage layout and used Linux / Oracle technology. Just for example: ZFS (e.g. with Solaris) with SSDs are great for L2ARC.

> b) What all filesystem we should plan on SSD ??

Once again - are you really talking about plain SSDs?

> c) What different architecture we should consider for ERP (OLTP) and BW (OLAP) ?

Well at first we need to know if you are using VMFS or RDMs. If you are using VMFs then the design maybe completely different than with RDMs. In addition it also depends on the vendor's specs.

> d) What should be RAID design for PRD and non PRD environment ??

What is your SLA? Are you using technology like Oracle ASM? Where do you plan to mirror?

> What is standard best practice, we are considering 20% SSD to meet our IOPS requirement as per SAPS calculation

Well the response time and IOPs depends on each vendor's specs, but as a rule of thumb to get the IOPs:

Old calculation based on DB and app server

• 2.5 SAPS (DB+App-Sv) generate 1 I/O operation per second
• 1 concurrent SAP NW user generates ~9 I/Os per second

New calculation based on DB server

• 0.3 DB-Server SAPS generate 1 I/O operation per second
• This new approach is based on that more SAPS are consumed on App-Server side relative to DB, but this will / may change with ABAP core data services for Oracle again
• Variation of DB-SAPS : App-SAPS is significant for different SAP modules (e.g 1:3 for ERP = OK versus 1:15 for CRM = too high I/O load for DB-Server)

Basically all of these questions can hardly be answered through an online forum as it all depends on your requirements and used technologies.

Regards

Stefan

[Former Member]

Thanks Stefan for your reply,

Actually I am not sure about SSD is plain or what, Vendor only suggested SSD (Flash Drives), I have checked about SSD and found 2 types of SSD exists multi Level (MLC) and single Level (SLC) and some recommendations on SLC side.

1) We are planning for VMFS instead of RDM, but what is your suggestion ?

2) Also checked that redo log is not recommended on SSD because of sequential writes Can you suggest what filesystem (SAPDATA) should we direct to SSD and normal SAS ??

3) Or will it only recommended for Cache and in case of cache what % of DB size ?

4) Any recommendation for OLAP and OLTP systems ?

5) For PRD we have planned RAID10 and other systems on RAID 5, Is this correct approach ??

Saurabh Mishra

[stefan_koehler]

Hi Saurabh,

> Actually I am not sure about SSD is plain or what, Vendor only suggested SSD (Flash Drives)

Please verify this with your vendors asap as this is a pretty critical information for you.

> 1) We are planning for VMFS instead of RDM, but what is your suggestion ?

Ok, thanks. Do you share one VMFS for all virtualised systems or have separate ones for each system? I can not make any suggestion without knowledge of the used / proposed storage architecture / technology. For example an IBM XIV works totally different than an IBM SVC + DS 8000 and also needs other LUN / storage designs.

> 2) Also checked that redo log is not recommended on SSD because of sequential writes Can you suggest what filesystem (SAPDATA) should we direct to SSD and normal SAS ??

At first you need to know where these SSDs are placed and how they should work in the proposed storage environment. For example SSDs are usually considered by an I/O throughput per disk of >1000 I/O per second (predominantly read). So the storage layout has to be designed that way, if you have systems that have these single requirements.

> 3) Or will it only recommended for Cache and in case of cache what % of DB size ?

Sorry, i don't get this question properly, but i guess you are talking about SSDs for caching here. This mainly depends on the technology. I am repeating all the time, but it is always the same core topic / issue. For example here is an article about the previously mentioned L2ARC cache in case of ZFS (it is for Solaris and has nothing to do with your environment, but just to get an idea that you really need to know where it is placed and how it should be used): ZFS L2ARC

> 4) Any recommendation for OLAP and OLTP systems ?

Not without any details.

> 5) For PRD we have planned RAID10 and other systems on RAID 5, Is this correct approach ??

I can not answer this.

Regards

Stefan