Raw devices remapping
We've just set up RAC on a 4-node linux cluster using RedHat AS 2.1
We're using raw-devices on a DELL|EMC SAN.
After reading some documents, we've realised that the sd devices can change if we add or remove some LUNz on the SAN.
Is there anyone with some experience on this issue?
Are there any way to avoid this situation?
Hi,
A raw device can be bound to an existing block device (e.g. a disk) and be used to perform "raw" IO with that existing block device. Such "raw" IO bypasses the caching that is normally associated with block devices. Hence a raw device offers a more "direct" route to the physical device and allows an application more control over the timing of IO to that physical device. This makes raw devices suitable for complex applications like Database Management Systems that typically do their own caching.
Raw devices are character devices (major number 162). The first minor number (i.e. 0) is reserved as a control interface and is usually found at /dev/rawctl. A utility called raw (see man raw) can be used to bind a raw device to an existing block device. These "existing block devices" may be disks or cdroms/dvds whose underlying interface can be anything supported by Linux (e.g. IDE/ATA or SCSI).
Try this command on linux and see
ls -lR /dev/raw*
Unix utilities such as recent versions of dd and lmdd (from the lmbench suite of programs) can be used to move data to and from "raw" devices as they meet the above-mentioned block alignment requirements. Recent versions of the sg_dd command in the sg_utils package can access both raw and sg devices.
Also note that if the physical device has an odd number of sectors the last sector will not be accessible using raw IO.
Main Advantages for Raw devices is that (Abstract View), When ORACLE writes to data on O.S, it takes time to do perform the task, since the Operating Systems is a layer between the Disk and the RDMS, where the Accessing is done. When compare to the Raw Device, where there is not O.S comes in to picture.. while performing the task of disk Reads and writes...since the Performance is High when compared to Normal Disk.. !!
- Pavan Kumar N
Similar Messages
-
How can I copy datafile (from one Raw device) to another Raw device ???
can anybody tell me how do i copy/move one datafile from one raw device to another raw device.... ?
I am having AIX 5.3 with SAN.
Pls. help me...
regards,
Star NiravHello Hans,
Currently I am using via RMAN... Want to know which one help me....? Is there any size limitation via dd command ? Can I use iocopy instead of dd in AIX ?
man dd -
Raw device for oracle 8.1.7 on AIX 4.3.3
Hi there,
I am trying to use a raw device on AIX 4.3.3 for ORACLE 8.1.7.
I have created a raw device /dev/or_system
brw-rw---- 1 oracle dba 54, 1 Mar 04 10:44 or_system
but it is not possible to create a datafile on it :
SVRMGR> create database "GLM"
maxinstances 8
character set "WE8ISO8859P1"
datafile '/dev/or_system' size 150M REUSE
logfile
GROUP 1 ('/oracle/GLM/redo/log1.ora') size 100M,
GROUP 2 ('/oracle/GLM/redo/log2.ora') size 100M,
GROUP 3 ('/oracle/GLM/redo/log3.ora') size 100M,
GROUP 4 ('/oracle/GLM/redo/log4.ora') size 100M;
create database "GLM"
ORA-01501: CREATE DATABASE failed
ORA-01519: error while processing file '?/rdbms/admin/sql.bsq' near line 407
ORA-00604: error occurred at recursive SQL level 1
ORA-01119: error in creating database file '/dev/or_system'
ORA-27038: skgfrcre: file exists
SVRMGR>
The ORA-27028 in exact this situation was reported as a bug in prior ORACLE Versions 8.0.4/ 8.0.5 and had
the bug no. 690228.
But we use as mentioned 8.1.7.
What do I do wrong?
Any suggestions are welcome.
Thank you
GerhardEach raw device you create is used as a single data file.
Eg mklv -y 'myfile' <vgname> <number of logical partitians>
Will have two special files associated with them /dev/rmyfile and /dev/myfile. The number of logical partitians will be the size of your datafile subtract 1 meg for overhead.
So, if you were addding the above raw volume to a tablespace, and the lp size was 32 meg, you would
create tabelspace tsname datafile '/dev/rmyfile' size 31 m;
Note the use of rmyfile not myfile. -
Hello,
I am getting the following error when I try to complete approval process.
ORA-20001: Unable to create tablespace. ORA-01
119: error in creating database file '//./FLOW_1.dbf' ORA-27040: skgfrcre: creat
e error, unable to create file OSD-04002: unable to open file O/S-Error: (OS 2)
The system cannot find the file specified.
I checked the alert log for error here is the error in the alert log file.
ORA-1119 signalled during: CREATE TABLESPACE FLOW_1 DATAFILE '//./FLOW_1.dbf'..
and i found the syntax for create tablespace was wrong.
To create a tablespace in RAC with RAW device environment under windows.
it should have forward black slash instead of backward slash "/" without .dbf extension.
so, I changed the syntax i was able to create tablespace through sqlplus.
When APEX tool try to create this tablespace it throws this error..
Old: CREATE TABLESPACE FLOW_1 DATAFILE
'\\.\FLOW_1.dbf' SIZE 10304 K REUSE AUTOEXTEND OFF
EXTENT MANAGEMENT LOCAL AUTOALLOCATE SEGMENT SPACE MANAGEMENT AUTO
error : ORA-01119: error in creating database file '\\.\FLOW_1.dbf'
New:
CREATE TABLESPACE FLOW_1 DATAFILE
'\\.\FLOW_1' SIZE 10304 K REUSE AUTOEXTEND OFF
EXTENT MANAGEMENT LOCAL AUTOALLOCATE SEGMENT SPACE MANAGEMENT AUTO
Tablespace created.
Is it a bug in APEX 3.0.1.??
Is anyone installed APEX in RAC ??
JamesHi,
One observation, Apex is switching the Session ID after one got killed ? I was working on Apex page with browse Item to test open cursor count,
after killing the SID (227) on which the open cursor count was getting increase, it APEX automatically switches to new SID(149) for that session.
Now the problem is even if I have two SID's and one hits the maximum open cursor count, It is not switching to other SID instead the whole application becomes unavailable.
STATNAME SID VALUE USER
opened cursors current 20 14 APEX_PUBLIC_USER
opened cursors current 149 74 APEX_PUBLIC_USER
opened cursors current 194 71 APEX_PUBLIC_USER
opened cursors current 211 5 APEX_PUBLIC_USER
opened cursors current 227 325 APEX_PUBLIC_USER Killed
opened cursors current 244 15 APEX_PUBLIC_USER
opened cursors current 20 14 APEX_PUBLIC_USER
opened cursors current 149 76 APEX_PUBLIC_USER
opened cursors current 194 71 APEX_PUBLIC_USER
opened cursors current 211 5 APEX_PUBLIC_USER
opened cursors current 244 15 APEX_PUBLIC_USER
Please kindly help in this.
Thanks in Advance
Thanks & Regards
Sanjay
Edited by: user11204334 on Dec 8, 2010 1:02 AM -
10g ASM on Logical Volumes vs. Raw devices and SAN Virtualization
We are looking at setting up our standards for Oracle 10g non-rac systems. We are looking at the value of Oracle ASM in our environment.
As per the official Oracle documentation, raw devices are preferred to using Logical Volumes when using ASM.
From here: http://download.oracle.com/docs/cd/B19306_01/server.102/b15658/appa_aix.htm#sthr
ef723
"Note: Do not add logical volumes to Automatic Storage Management disk groups. Automatic Storage Management works best when you add raw disk devices to disk groups. If you are using Automatic Storage Management, then do not use LVM for striping. Automatic Storage Management implements striping and mirroring."
Also, as per Metalink note 452924.1:
"10) Avoid using a Logical Volume Manager (LVM) because an LVM would be redundant."
The issue is: if we use raw disk devices presented to ASM, the disks don't show up as used in the unix/AIX system tools (i.e. smit, lspv, etc.). Hence, when looking for raw devices on the system to add to filesystems/volume groups/etc., it's highly possible that a UNIX admin will grab a raw device that is already in use by Oracle ASM.
Additionally, we are using a an IBM DS8300 SAN with IBM SAN Volume Controller (SVC) in front of it. Hence, we already have storage virtualization and I/O balancing at the SAN/hardware level.
I'm looking for a little clarification to the following questions, as my understanding of their responses seem to confict:
QUESTION #1: Can anyone clarify/provide additional detail as to why Logical volumes are not preferred when using Oracle ASM? Does the argument still hold in a SAN Virtualized environment?
QUESTION #2: Does virtualization at the software level (ASM) make sense in our environment? As we already have I/O balancing provided at the hardware level via our SVC, what do we gain by adding yet another level of I/O balancing at the ASM level? Or as in the
arguments the Oracle documentation makes against using Lvm, is this an unnecessary redundant striping (double-striped or in our case triple-striped/plaid)?
QUESTION #3: So does SAN Virtualization conflict or compliment the virtualization provided by ASM?After more research/discussions/SR's, I've come to the following conclusion.
Basically, in an intelligent storage environment (i.e. SVC), you're not getting a 100% bang for the buck by using ASM. Which is the cat's meow in a commodity hardware/unintelligent storage environment.
Using ASM in a SVC environment potentially wastes CPU cycles having ASM balance i/o that is already balanced on the backend (sure if you shuffle a deck of cards that are already shuffled you're not doing any harm, but if they're already shuffled - then why are you shuffling them again??).
That being said, there may still be some value for using ASM from the standpoint of storage management for multiple instances on a server. For example, one could better minimize space wastage by being able to share a "pool" of storage between mulitiple instances, rather than having to manage space on an instance-by-instance (or filesystem by filesystem) level.
Also, in the case of having a unfriendly OS where one is unable to dynamically grow a filesystem (i.e. database outage required), there would be a definite benefit provided by ASM in being able to dynamically allocate disks to the "pool". Of course, with most higher-end end systems, dynamic filesystem growth is pretty much a given.
In the case of RAC, regardless of the backend, ASM with raw is a no-brainer.
In the case of a standalone instance, it's a judgement call. My vote in the case of intelligent storage where one could dynamically grow filesystems, would be to keep ASM out of the picture.
Your vote may be different....just make sure you're putting in a solution to a problem and not a solution that's looking for a problem(s).
And there's the whole culture of IT thing as well (i.e. do your storage guys know what you're doing and vice versa).....which can destroy any technological solution, regardless of how great it is. -
How to setup the raw devices permissions permanantly in 11gr2 on RHEL 5.
Hi All,
Succesfully installed 11gr2 RAC and working fine , but in next boot raw devices permissions revert back to root .
Please advice me to how to setup permissions permanantly as the oracle user.
Regards
San
.you find the lib on this page:
http://www.oracle.com/technetwork/topics/linux/downloads/rhel5-084877.html
in the AMD64 / Intel em64t Architecture table
this is the direct link
http://oss.oracle.com/projects/oracleasm/dist/files/RPMS/rhel5/amd64/2.0.5/2.6.18-194.el5/oracleasm-2.6.18-194.el5xen-2.0.5-1.el5.x86_64.rpm
hth
p.s. don't forget to mark question as helpful/correct and close the question. -
How to create DIR/File on a raw device in RAC environment.
Hi all,
I use a shell script to create DIR and File on a raw device also it creates schema and tablespaces.
I am facing problem in creating DIR and Files on raw device.
One more thing, can multiple tablespaces be created on a raw device.
Thanks & regards,
SanjeevThanks for the response. Please help me further.
About the Script - It asks for the path for creating DIR and uses shell command to create DIR. Later same path and DIR name is used to create Oracle DIR. Now in place of absolute path raw device name is passed. The same script is also used for creating tablespaces and schema.
There is second script that is .sql script that creates external table in the newly created schema. All this has been working fine on single instance Oracle server. we have tested many times but fails in RAC environment when we use raw device.
Question is - If I use filesystem will the external table's flat files and Directories be accessible to all the instances.
I have one application written in java that would be clustered and running on these oracle servers. This application would be accessing those external tables and their flat files. Will there be a problem accessing these flat files accross the instances.
Regards,
Sanjeev. -
HI ALL,
in redhat linux 5 how to format the disk(ex: /opt,/u01,.....) and make it as raw device for ASM installationDSP_863977 wrote:
HI ALL,
in redhat linux 5 how to format the disk(ex: /opt,/u01,.....) and make it as raw device for ASM installationit is not possible to change a mount /opt or /u01 for ASM storage.
for learning purpose you can learn with vmware server to create a raw device to configure/install ASM.
Refer the link:- shared storage part for linux5/rhel5
http://oracleinstance.blogspot.com/2010/03/oracle-10g-installation-in-linux-5.html
for more information refer the link:-
http://download.oracle.com/docs/cd/B28359_01/server.111/b31107/asmprepare.htm -
Content Server 6.40 on Raw Devices
Hi Folks!
We'd like to install a Content Server 6.40 using raw devices (on Linux Suse SLES9).
Do we need to install the MaxDB, if we use raw devices? At this point the InstGuide does not give a clear description of what to do. It looks we can use the raw devices directly without having a database instance. Is this right?
Is there any disadvantage compared to using the access via file system and DB?
Any hint is appreciated...
Best regards
TorstenHi Torsten,
As far as i know SAP Content Server use MaxDB or a File System, I have use it with MaxDB with good results, anyhow.... read the following for details,
http://help.sap.com/saphelp_nw04s/helpdata/en/40/32104211625933e10000000a155106/content.htm
Regards
Juan
Please reward with points if helpdul -
Good morning,
I would like to make some i/o test with a database version 10g, actually I have the redo log on standard zfs filesystem (cooked), I would like to
migrate this redo log on raw device without recreating the database, is this possible ?
Thanks for your help
Fabrice ChapuisOne more question, in case of node failure , redo on raw device are more critical for a recover than if they were on a filesystem ?More critical? Or more difficult?
Redo is critical, period. Does not matter whether you use a cooked file system or a raw device.
As for difficulty - that depends on what you are attempting to do. If you want to treat the raw device as a file system, that will be difficult as it it not a file system. (which kind of begs the question as to treat it like a file system when it is not?)
From a RMAN perspective - a device is a device. RMAN does not care.
From a DB perspective - that is why ASM exist. To remove the complexities of using raw devices, and eliminate the requirement of needing to use an external Volume Manager. And provide the DBA with a familiar SQL*Plus interface and SQL commands to administer ASM.
It may seem difficult at first - but anything that needs a learning curve to go through, tends to seem difficult in the beginning. All you need to do is learn the basics and grasp the concepts.. and that +"difficulty"+ disappears. -
10.1.0.3 on RH4(Centos) + Raw devices + ASM + RAC
Hi,
I'm just wondering if anyone here tried installing a single node RAC on 2 instance using ASM on Oracle 10g (10.1.0.3)?
I am using RH4(CENTOS 4.1), Oracle 10.1.0.3 + CRS 10.1.0.3 on fake raw devices in Linux.
I have been able to install the CRS and Oracle database software successfully.
All CRS services and listener are up and running.
crs_stat command return successful results.
srvctl status nodeapps -n <node_name> also returns successful results.
However, when I attempt to startup the ASM instance, I keep encountering these errors:
ORA-00603:ORACLE server session terminated by fatal error
ORA-27504:IPC error creating OSD context
The ORA-00603 error message will appear immediately in the SQLPLUS prompt when I try to startup ASM instance.
Both errors will be logged in alert.log and trace files, no other useful error messages besides these errors.
When I attempt to create a normal database instance using datafiles on the same machine, these errors also appear again!
So, I figure its got nothing to do with the raw devices since my OCR location and Voting devices are using the same raw devices on Linux.
Anyone did the same thing like me and faced similar problems.... please help.
CheersYou can use dbca to create ASM instance to get rid of the manual copy business.
In realease 1, you can invoke dbca, choose database instance and walk through still you reach storage clause and choose asm and DBA will create ASM instance on both nodes.
Ensure that you choose cluster install option and all the nodes at the initial stages. -
Raw Device Validation Check for Name Failed..
Hi all,
I have installed Oracle Clusterware 10.2.0.4 and Oracle database software 10.2.0.4 on Solaris SPARC 10 and i using a NAS storage for the same
And when i try to create a database using DBCA i got the following error.
Raw Device Validation Check for Name /u03/oradata/spfile/spfile{SID}.ora failed. The specified file /u01/oradata/spfile/spfile{SID}.ora doesnot exit.Please a existing file.
Note: i am not using ASM., i am using RAW device for Database
Any help highly thankful
-ArunHi
this is how i have mounted the NAS...
10.0.0.0:/vol/prodt3_vol16/ora_dbfr_inn1s - /u07/DBFR/INS nfs - yes rw,bg,hard,nointr,rsize=32768,wsize=32768,proto=tcp,noac,forcedirectio,vers=3,suid
how do i ensure that it is not being used....we should not use ASM its an client requinment ...
Thanks -
Cold backup of controlfile raw device
We have Oracle 9.2.0.4 on AIX 5L on node 1 and node3 with controlfile as raw device. These two nodes are connected through LAN. I shutdown the database DB on node1 and take the backp of controlfile in /ora/backup on node1 usind dd command. I mput this file in binary mode on node3 over ftp. On node3 when I tried to mount the database using this controlfile it gave error
"ora-0201- controlfile version incompatible with oracle version."
In alert log it showed the message
Corrupt block relative dba: 0x00000001 (file 0, block 1)
Fractured block found during control file header read
Data in bad block -
type: 0 format: 0 rdba: 0x00000000
last change scn: 0x0000.00000000 seq: 0x0 flg: 0x00
consistency value in tail: 0x00000000
check value in block header: 0x0, block checksum disabled
spare1: 0x0, spare2: 0x0, spare3: 0x0
What can be the exact problem?? Any hlep.Why are you mounting or doing this ? I think databases on node1 and node3 are not the same. Controlfile of a database cannot be used to mount a different database.
fyi,
ORA-00201 controlfile version string incompatible with ORACLE version string
Cause: The control file was created by incompatible software.
Action: Either restart with a compatible software release or use CREATE CONTROLFILE to create a new control file that is compatible with this release. -
Create a physical standby for Rac on Windows and raw devices
Hi buddies:
I need to create a Physical standby database for a 2 node RAC cluster on Windows, that is using RAW devices.
Can someone of you suggest me a note to follow in order to achive this, i can not find to much information about how to do this.
I guess that the best option would be to use RMAN to do this, but as i said before i havent found too much information.
I would really appreciate your help.
Kind regards
MQIn this case the standby should be created as a single instance on regular files.
Do i have to specify something different in the duplicate rman command to specify that the standby database will be a single instance?
Thanks for your help
MQ -
Database in Raw device recover in time tablespace
How recover database in raw device using clone database
(Recovery Manager) ?
The problem is follow:
When RMAN begin then recover proces he need create the clone
database. @ How create this database ? @ In file system or raw
device ? if he create it in raw device @ Then device necessary
must be created before ?
@ How many devices ? @ What is your size ?
Thanks ...
nullWith raw devices alternative cost of performance is typical management difficulties like this, but after 10g ASM is a big shift - http://www.dbazine.com/olc/olc-articles/still5
http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/storeman.htm#i1021337
Best regards.
Maybe you are looking for
-
Limit user Access to Return Data in Report
Have reporst that I need to limit what is returned. The person running the report should only see the data that they own. Is this possible. Can I set an attribute based on the person who has signed on to Discoverer and use that in the select to limit
-
How to insert XML/dtd data into oracle db
Hi, I have posted this question on couple sites and unfortunately I haven't received any response. Hopefully this time, someone can at least direct me to the website/document/sample codes which can provide me solutions of my question. My question is:
-
Caption in the Variable Selection Screen
Hi, I have my queries in web templates on WAD. I want to attach a description for each report which shows on the top of the selection screen, how can I do it. For example i have a P&L monthly report with the selection screen include a selection for F
-
IBooks item no longer available in Australian store
# I just sent this to Apple support,which I think outlines my situation. I thought it worth asking here also # The support page wouldn't allow me to post, so I took some others advice and kept original post a sentence...that seems to work...then edit
-
Itunes freezing and getting a Device Timeout error
i just got my ipod and was loading songs into the itunes library, everything was fine, then i loaded some songs and itunes froze and was not responding when i tried again, same problem the top of itunes says it's "determining gapless playback informa