Question(s) related to ASM, Raw devices and performance

Good morning,
I was recently getting acquainted with ASM. Since I was doing this in "play" VM boxes, it was not possible to draw any conclusions about any performance improvements.
I'd like to know what performance improvements forum members may have experienced after migrating a production environment from a non-ASM setup to an ASM setup.
It would seem that since ASM is a "form" of raw device access that the increase in performance should be noticeable. Was that the case for those who migrated to it ? Was the performance improvement worth it or did it only make managing the database easier ?
Thank you for your contributions on the subject,
John.

ASM uses disk groups to store datafiles; an ASM disk group is a collection of disks that ASM manages as a unit. Within a disk group, ASM exposes a file system interface for Oracle database files. The content of files that are stored in a disk group are evenly distributed, or striped, to eliminate hot spots and to provide uniform performance across the disks. The performance is comparable to the performance of raw devices.
You can add or remove disks from a disk group while a database continues to access files from the disk group. When you add or remove disks from a disk group, ASM automatically redistributes the file contents and eliminates the need for downtime when redistributing the content.
I hope the links below will helps you.
refer the links:
http://download.oracle.com/docs/cd/B28359_01/server.111/b31107/asmcon.htm
http://oracleinstance.blogspot.com/2009/12/rac-file-system-options-basic-concept.html
http://www.dbasupport.com/oracle/ora10g/ASM01.shtml
also you will get more information from book:
Oracle Automatic Storage Management: Under-the-Hood & Practical Deployment Guide (Osborne ORACLE Press Series)
Nitin Vengurlekar (Author), Murali Vallath (Author), Rich Long (Author)
http://www.amazon.com/Oracle-Automatic-Storage-Management-Under/dp/0071496076

Similar Messages

Raw Device and ASM configuration

Can any body send me steps/commands to configrue Raw device and then ASM on top of it for RAC?

Try this:
http://download-east.oracle.com/docs/cd/B19306_01/server.102/b14231/storeman.htm#i1021337
And this for installing 10g RAC on RH:
http://www.puschitz.com/InstallingOracle10gRAC.shtml
Daljit Singh

I've logged onto iTunes, but it's asking me security questions because it's a new device, and I'm getting the answers wrong, but iTunes wants to reset but send the new passwords to my ex partners email address how can I get round this.

I've logged onto iTunes, but it's asking me security questions because it's a new device, and I'm getting the answers wrong, but iTunes wants to reset but send the new passwords to my ex partners email address how can I get round this.

I believe part of the recovery process is you get an e-mail allowing you to reset questions. If that e-mail isn't correct either because your son set it up then you really have no option but to ask Apple again. They are getting strict abotu security and given the number of "My iTunes account got hacked" posts here I can guess why. They have no way of knowing you really are the owner of the account. It's like me going to a policeman and saying, "See that car over there? That is mine, can you open the door for me?" and the police opening it on that basis alone.
Frequently asked questions about Apple ID - http://support.apple.com/kb/HE37 --> Can I change the answers to the security questions for my Apple ID? --> Yes. You can change the answers to the security questions provided when you originally signed up for your Apple ID. Go to My Apple ID (http://appleid.apple.com/) and click Manage your account.
Forgotten security questions - https://discussions.apple.com/message/18402551 and https://discussions.apple.com/message/18625296
More involved forgotten question issues - https://discussions.apple.com/thread/3961813
Kappy 09/2012 post about security questions - https://discussions.apple.com/message/19569468
John Galt's tips (09&11/2012) - https://discussions.apple.com/message/19809294 and https://discussions.apple.com/message/20229239
If none of the above work, contact iTunes Support at http://www.apple.com/support/itunes/contact/ and follow the instructions to report the issue to the iTunes Store.

Difference between raw device and a block device

Platform : Unix, Unix-like
What is the difference between a raw device and a Block device? I found the following URL by googling. But, posts seem to be mutually contradictory
http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1291798907338+28353475&threadId=583811

a raw device is a special kind of block device file that allows accessing a storage device such as a hard drive directly, bypassing the operating system's caches and buffers (although the hardware caches might still be used). Applications like a Database management system(Oracle ) can use raw devices directly, enabling them to manage how data is cached, rather than deferring this task to the operating system.
block devices correspond to devices through which the system moves data in the form of blocks. These device nodes often represent addressable devices such as hard disks, CD-ROM drives, or memory-regions.
Also Check :
http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1291806443666+28353475&threadId=987277
Regards
Rajesh

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.

Raw device and Oracle

Hi,
did anybody successfully test Stephen Tweedy3s raw device against
Oracle? I testet also against Sybase but could not get it to run.
Stephen checked straces and stuff but there seems to be no error!
Look at ftp.uk.linux.org/pub/linux/sct/fs
This patch is against Linux 2.2.9.
Please people, test it and tell me if it works for you
Cheers
Marcus
null

Marcus Ruehmann (guest) wrote:
: Hi,
: did anybody successfully test Stephen Tweedy3s raw device
against
: Oracle? I testet also against Sybase but could not get it to
run.
: Stephen checked straces and stuff but there seems to be no
error!
: Look at ftp.uk.linux.org/pub/linux/sct/fs
: This patch is against Linux 2.2.9.
: Please people, test it and tell me if it works for you
: Cheers
: Marcus
Hi Marcis,
I tested raw device with Oracle but in AIX with Oracle 7.3 and
it worked perfectly. While I'm waiting for Oracle8i on Linux and
would test it with raw device, I don't think there would be too
much different.
Brdgs,
Quoc Trung
null

Some question about communicating the usb RAW device

I have some question about USB communication: I want to make my VI communicate
TI-DSP by USB, now, the driver of USB on DSP have done, and there are a test
program writen by VC and a driver fold(with a .inf and a .sys files), when I
install the driver and run the test program, the driver program on DSP run
regularly. And then I want to program a VI which have the same function as the
test program, so I unload the driver on PC firstly, then install the DSP in
NI_VISA according to "Using NI-VISA 3_0 to Control Your USB Device - Tutorial -
Instrument Drivers". When I sent the standard control request using the VISA test panel, the status below happened. I don't know what wrong with my step.
Dev Phase Data                       Info           Time   Cmd.Phase.Ofs
15 CTL    80 06 03 00 - 00 00 04 00 GET DESCRIPTR 5.2sc        56.1.0
14 CTL    80 06 03 00 - 00 00 04 00 GET DESCRIPTR   11us        57.1.0
14 USTS   00 00 01 c0                canceled       2.0sc        57.2.0
15 USTS   00 00 01 c0                canceled         5us        56.2.0
PS: the software I use to capture the data is BUSHOUND
1、Do I have to install the .sys driver file in VISA? How can I install the driver file without losing the device in MAX?
2、Someone told me it must be done by calling .dll fies in LV, but I want to know if LV can program the function directly without calling .dll file?
Thank for any reply~~!

逍遥浪子 wrote:
I have some question about USB communication: I want to make my VI communicate TI-DSP by USB, now, the driver of USB on DSP have done, and there are a test program writen by VC and a driver fold(with a .inf and a .sys files), when I install the driver and run the test program, the driver program on DSP run regularly. And then I want to program a VI which have the same function as the test program, so I unload the driver on PC firstly, then install the DSP in NI_VISA according to "Using NI-VISA 3_0 to Control Your USB Device - Tutorial - Instrument
Drivers". When I sent the standard control request using the VISA test
panel, the status below happened. I don't know what wrong with my step. Dev
Phase
Data
Info
Time   Cmd.Phase.Ofs     ---
----- ------------------ 15
CTL    80 06 03 00 - 00 00 04 00 GET
DESCRIPTR 5.2sc
56.1.0        14
CTL    80 06 03 00 - 00 00 04 00 GET
DESCRIPTR   11us
57.1.0        14
USTS   00 00 01
c0
canceled
2.0sc
57.2.0        15
USTS   00 00 01
c0
canceled
5us        56.2.0 PS: the
software I use to capture the data is BUSHOUND 1、Do I have to install the .sys driver file in VISA? How can I install the driver file without losing the device in MAX? 2、
Someone told me it must be done by calling .dll fies in LV, but I want
to know if LV can program the function directly without calling .dll
file?
This thread
contains already a related answer and explains what a sys driver is.
While you could theoretically use the Call Library Node to call all the
necessary Win32 API kernel functions to connect to a device driver,
this would be very cumbersome and not doable without a real good
understanding about C programming. Writing an interface DLL instead
won't need more C programming knowledge at all but will give you a
clean interface to that device driver which eventually could be used in
other programming environments as well.
Rolf Kalbermatter
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Raw devices and cluster file system

what is difference between raw and cluster file system

See to this thread if this can help
http://asktom.oracle.com/pls/asktom/f?p=100:11:3285616048047775::::P11_QUESTION_ID:7931107631402

PhotoStream: Multiple Devices and Performance Issues

Had a bad night last night with PhotoStream. I have an iPhone 4S (AT&T), my wife has an iPhone 4 (VZW), we have an iPad 1 (Wi-Fi), Apple TV 2 (Ethernet), and a 2011 Mac Mini (Wi-Fi)... all in the same house that has a Time Capsule and is connected to AT&T DSL service, 3.0Mbps service (average speed test results are 2.65Mbps down, 315kbps up). Oh yeah, there's a micro-cell in there too but anytime there's trouble that gets shut off first so its irrelevant for this discussion.
So yesterday was Halloween and we both took alot of photos away from the house with the iPhones. Got home, started using the internet, noticed the performance was HORRIBLE. Speed test showed over 1,000 ms ping latency (I still can't believe I actually waited for it to finish the ping test) and nothing was getting through for the download / upload test. I have never (believe it or not) with AT&T DSL seen it get this bad. Its been bad before, don't get me wrong, but this was surprising even to me.
How did I come to the conclusion that PhotoStream was my issue you may ask? Well, its sort of a long story, but bear with me... The other day, we started having trouble with the Apple TV 2, which for the most part is pretty solid. My wife was streaming Netflix movies and it was stopping every 30 seconds. It was looking at this issue that had me first raise suspicions about PhotoStream. Just days before this problem started, I had enabled PhotoStream on the Apple TV 2. SO I did the first most logical thing anyone could do, I took a step back and disabled it. Problem solved. Thought nothing of it, yeah I was a little discouraged that I couldn't use it on the Apple TV 2, but not a big deal, my favorite part of PhotoStream is using it to get the photos into iPhoto without having to plug the iPhones in so I said to myself "I'll just keep putting the photos into Events and Albums until they work out the kinks on the AppleTV 2" thinking perhaps the Apple TV 2 needs to not update PhotoStream while videos are being played. They can fix that at some point, right? Sure they can.
Now, back to this other issue. My bandwidth last night was completely crapped out, and I was determined to prestige on Black Ops one last time so this had to change STAT! I mean, come on! I was at Level 47 and I was ready to GO! My internet connection just wasn't having it. I powered off the router, rebooted the modem, and powered on the rotuer again. Everything came up beautifully. I jumped into some Nuketown 24/7, 4 green bars next to my name and I was happy. After we lost Bravo, which on Nuketown takes about a minute and a half if both teams are fighting over it, I'm lagging like crazy and I have that little red bar that no one likes to see next to my name. Sure enough, speedtest results are all whacked out again.
So I'm sitting there thinking to myself, what could this be? My wife was watching cable TV, my son was asleep... essentially the Xbox 360 was the only thing trying to use the internet... I thought... until I remembered our iPhones and the photos we had just taken and all the devices that would be simultaneously trying to update PhotoStream. Let's list them again, shall we?
iPhone 4S - Upload to Stream and Download from Stream
iPhone 4 - Upload to Stream and Download from Stream
iPad 1 - Download from Stream
Mac Mini - Download from Stream
So how can I prove this crazy theory of mine that the great and wonderful PhotoStream was choking my internet connection? Simple.
iPhone 4S - PhotoStream OFF
iPhone 4 - PhotoStream OFF
iPad 1 - PhotoStream OFF
Mac Mini - PhotoStream OFF
Speed test results immediately after doing this?
2.73Mbps down / .31Mbps up with 26ms ping time (used the Speedtest.NET app on the 4S).
Sadly, this means that for now, I cannot use PhotoStream, however I did manage to Prestige on Black Ops which made me happy, and the iPhone 4S can still be plugged into the Mac Mini to download my wonderful looking photos.
That's right, I didn't throw away the charger cables just yet and if you want to start talking about iTunes Wireless Synching with multiple devices in the same house, I can gladly take up some more of your time. Thats right, its OFF as well!

I just wanted to report that this is still an open and particularly nefarious bug. I've got a fairly idealized Apple household with 2 iPhone 4's, a 'new' iPad, a 13" Macbook Pro, Airport Express and our most recent addition this weekend... an Apple TV.
While I had no particular interest in enabling Photo Stream, I turned it on while messing with the screen saver settings and didn't think anything about it. As I began to play with my new toy I was immediately disappointed with all the long spinners and timeouts in Netflix. Later that day I noticed my computer and iPad were having similar connection issues. My first thought was 'oh, Comcast must be acting up, that's why my new Apple TV isn't working so well'.
Fast forward 3 days to today and our network issues were still occuring and I decided I needed to figure out what was going on. After mucking around in network settings for a couple hours I half-jokingly decided to disconnect the AppleTV on the whim that the issues started at the same time I hooked it up. Sure enough my network issues disappeared. I even went so far as to run continuous pings to various IP's outside my home network and watch the timeouts come & go as i plugged/unplugged my ATV. Now knowing the ATV was the problem I set out to figure out what in particular was causing it. As soon as I signed out of Photo Stream everything was working perfect again. Netflix on the ATV is quick & responsive, no more spinners or timeouts. My other devices aren't plagued with random disconnects, dns failures or slow downloads.
Long story short, something is bugged in AppleTV's Photo Stream support. Mine didn't appear to be downloading any new photos, it had stopped with 255 photos downloaded. Not sure if that was all I had in iCloud or maybe AppleTV can only pull down 255 max? Maybe 255 is the magic number where it hits the bug that causes this behavior? Either way, it appeared to be only affecting the outgoing internet connection, when I had a continous ping going to another machine on my internal LAN it didn't appear to get affected.
Hope this helps someone at Apple track down the bug. While someone technical can probably troubleshoot these issues I could see someone like my mom never putting the 2 + 2 together that her internet problems started around the time she enabled Photo Stream on her AppleTV and instead blaming it on 'the internet acting up again' and of course calling me months later to look into it for her.

Oracle ASM installation and raw device options

I am looking to install Oracle ASM on Linux Red Hat AS 4 (ia64) using Oracle 10.2.0.3.
A general question I have regarding prerequisites for ASM using raw devices. It appears there are 2 options for dealing with RAW devices.
1. Use the ASM library driver
or
2. simply bind the devices to raw devices (and then install a new $OH with an ASM instance)
Is there a recommendation from Oracle, industry best practices, expert opinions on which way to go?
If I understand correctly it sounds like option 2 will require an ASM $OH and instance. Is that right or do both option require this?
Can someone provide guidance as to which option I should use, an Oracle whitepaper, a recommendation, instructions or something.
Any help or insight is provided as to which option I should use.
Thank you.
echardrd

OK. Perhaps I am a little condused then. From what I read Oracle ASM recommends the use of RAW devices for ASM storage devices. What I have is a new LUN presented to my database server from the SAN. I assumed that the LUN needs to be mounted in some fashion on the server, but my SA tells me in order to mount it, would require the use of a filesystem. If we put a filesystem(NTFS, ext, etc) on the LUN prior to mounting it, will ASM be able to use it? If ASM can use a device that has a filesystem on it will this add unneccessary overhead (I/O)?
I guess my question is for ASM should I
1. use a RAW partition or a filesystem? Does it matter?
2. Will RAW have better I/O performance?
3. How do i make the LUN presentation from the SAN a usable RAW device to my database server? Any steps or guidance would be helpful since my SA and I can not seem to bridge this gap.
Thanks.

How to check space on asm and raw device?

Hi All,
I want to know how to check the space on asm device.
we are using asm device which is on raw partition.
Our archive gets full.I need to check the space on asm archve partiotion.
how can i check the archive destination space?
we are using raw device partition for crs and voting device.
how can we check the space on raw device and how can we know which device is in use and which are not in use
Thanks in advance

4 - 5 raw partitions...
What oracle version?
Install OCR + VOTE in raw device better than OCFS2. if you use 10g to 11gR1.
If use 11gR2,keep OCR + VOTE in ASM Disk Group.
you can check which raw device OCR:
$ ocrcheck
VOTEDISK:
$ crsctl query css votedisk
On 10g if use raw device for OCR + votedisk: recommend 1 file = 250M
11g recommend 1 file = 512M
Good Luck

ASM cannot find the raw devices nor ASM drives

Hi,
We are trying to use ASM on linux. The kernel version is
2.6.9-42.0.10.0.1.ELsmp x86_64.
We tried both raw devices and ASM drives. But after all the tries, the installer simply will not list the disks.
Anybody can help? Thanks.

"I had installed ASM initially on the same CRS, but due to some error during the installation"
This statement means: I had installed ASM on the clusterware, but due to time synchronization error, it didn't got copied on to the 2nd node, and hence I had to uninstall the ASM software.
But the clusterware is still up and running.
Amit.

Linux RedHat 4 update 4: how to unbind raw devices used by ASM diskgroups?

How to unbind raw devices used by ASM diskgroup?
I created ASM diskgroup using /dev/raw/rawn, after done my testing, I need to toss the raw devices to start a new testing. Here is the procedure:
1. shutdown MYTEST database
2. in ASM instance, remove disks from diskgroup 'rawtest'
3. in ASM instance, "drop diskgroup rawtest including contents"
4. in OS, issue: "raw /dev/raw/raw1 0 0"
I got the following error:
# raw /dev/raw/raw1 0 0
Error setting raw device (Device or resource busy)
But if I shutdown ASM instance, the above commmand will be successful.
My question, how can I unbind raw devices without shutting down ASM instance(could be used by other databases at the same time)?
Thanks,
Jenny

The installation guild will probably be were you will want to start.
2.11 Preparing Disk Groups for an Automatic Storage Management Installation
http://download.oracle.com/docs/cd/B19306_01/install.102/b15660/pre_install.htm#sthref457
Specifically
2.12 Configuring Raw Partitions or Raw Logical Volumes
http://download.oracle.com/docs/cd/B19306_01/install.102/b15660/pre_install.htm#sthref591

Using raw device

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 Chapuis

One 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.

Raw devices for 11g rac

hi,
whether 11gr2 rac supports raw devices in ibm aix 6.1 with power ha?
regards
sridhar

Hi;
Pelase see:
Raw Devices and Cluster Filesystems With Real Application Clusters (RAC) [ID 183408.1]
For your future RAC related issue I suggest close your issue here as answered than move your issue Forum Home » High Availability » RAC, ASM & Clusterware Installation which is RAC dedicated forum site.
Regard
Helios

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