on 01-20-2014 7:25 PM
Hi all
My professional path has always been around Windows/SQL Server, but I recently started to work on SAP on linux/oracle. I'm only in a learning stage.
I have read instguide and all notes related, but I still have one area that I don't understand: storage in linux.
In Windows you configure the storage on disks. You can have multiple local physical disks, or SAN LUNs represented in Windows as a disk. You then distribute the SAP and Database components through the different disks. You can add/remove/configure disks in administrative tools, and you can see them in the OS, represented by a drive letter.
Can someone give me an insight (or maybe provide some documentation) on what are you do on Linux? I did not find anything on Linux/Oracle instguide or related notes (Windows/SQL instguide describes these steps pretty well).
Can you have multiple disks? Do you separate components through disks? Best practices?
Thanks
Hi,
In Unix/Linux we distribute data in different filesystems, For example in Windows you would have 😧 drive for SAP executable, E:\ drive for Oracle/MSSQL data files. Similarly in Linux, from the LUN we will create different file systems and distribute the data like
\usr\sap - 5GB
\usr\sap\<SID> - 20 GB
\oracle - 5GB
\oracle\<SID> - 10GB
\oracle\<SID>\SAPDATA1 - 100GB
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Hi Pedro,
You asked:
1) Can you have multiple disks?
The answer is yes. As explains above, windows has C drive, D drive but in Linux, is /c /d
/ = root is something like C drive but when you add another drive you can't have a D drive.
You will need to map it to /<foldername> , means only one root instead of many as in windows.
2) Do you separate components through disks? Best practices?
It really depends.
For example, in windows we can install everything on C drive and configure even 'usr' folder on C but commonly you will separate the usr folder to D drive as in OS is one drive and data is another.
Similarly, we can have one disk (one disk may not be physically one disk), for / where your OS is and /usr is actually another disk (another set of physically disks) where the data resides.
Corinna
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Hi Pedro.
On Linux, like Unix in general, storage is not organized in one or more disks that each has a file system tree on it.
Instead, the operating system by default knows about exactly one single file system tree that is starting at the root node ('/').
When you are adding disks, logical volumes or disk partitions, you are first creating a sub-filesystem on them, similar to 'formatting' in Windows/DOS.(mkfs is the command)
Then you attach this newly created filesystem to a point within the root filesystem on your Linux/unix computer. This step is called 'mount'-ing.
Now, everytime you create a file in the directory where the new disk/partition is 'mount'-ed, it is in fact written to this new disk/partition.
The command 'df' shows you all disks/partitions known to the operating system and where they are mounted within the filesystem tree.
So the handling of space on different disks is completely hidden from application programs as the filesystem tree provides an abstraction layer from the underlying storage structures.
Hope that helps
Andreas
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Thanks for the help. Still trying to figure this out...
Also, KERVADEC, obviously i tried to read and google a lot before open this thread (most of the links i knew already), but its a bit confusing (to me, at least) how to configure filesystems for SAP.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Hi
There is a wiki on Linux with all the SAP notes
SAPonLinuxNotes - Wiki - SCN Wiki
For disk subsystem you should use LVM, read the installation note
1310037 - SUSE LINUX Enterprise Server 11: Installation notes
Using raw devices, Journaling File System, and LVM
The SAP note 405827 contains information on the usage of raw devices as well as Journaling File Systems.
A detailed discussion about file systems and their usage is available at:
http://wiki.novell.com/index.php/File_System_Primer
Note that the Linux kernels used in SLES 11 and SLES 10 systems implement the so called LVM2 (LVM Version 2) format.
The LVM2 format is recommended.
Check also that note
405827 - Journaled file system and raw devices on Linux
And give a try to that magic tool called Google, please, help yourself
https://www.suse.com/documentation/sles_for_sap/pdfdoc/sles_for_sap_guide/sles_for_sap_guide.pdf
https://www.suse.com/documentation/sles_for_sap/sles_for_sap_guide/data/s4s_inst_wizard.html
Regards
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.