How do I know disk block size of OS?

Which command? Can I change it?
Thanks.

Which command? If you have ext2 filesystem you should execute "tune2fs -l /dev/cciss/c0d0p6'
Can I change it?Yes,byt you should re-create filesystem. See "man mkfs.ext2 "
Thanks. It depends on type of your filesystem.
As I know the lagest block size is 4k.
Best regards.

Similar Messages

How should be set Index block size in Warehouse databases?

Hi,
We have Warehouse database.
I cannot find out index block size.
1. Where can I get know our index block sizes?
2. How can I enlarge index block sizes? Is it related with tablespace?
After your suggestion do I need increase or set buffer cache keep pool according to block sizes? 2K, 4K, 8K, 16K and 32K can be specified?
could you help me please?
thanks and regards,

See the BLOCK_SIZE column in DBA_TABLESPACES.
You can't "increase" the block size. You'd have
a) to allocate DB_xK_cache_size for the new "x"K block size
b) create a new tablespace explicitly specifying the block size in the CREATE TABLESPACE command
c) rebuild your indexes into the new tablespace.
Indexes created in a tablespace with a larger block size have more entries in each block.
You may get better performance.
You may get worse performance.
You may see no difference in performance.
You may encounter bugs.
"increasing block size" is an option to be evaluated and tested thoroughly. It is not, per se, a solution.
Hemant K Chitale
http://hemantoracledba.blogspot.com

How do I know which block has been changed in Master/Detail

Hi,
I have master detail blocks. How do I know which block has been changed?
I used :SYSTEM.FORM_STATUS. It only gave me "Changed" or "Query". but didn't tell me which block has been changed in MASTER or DETAIL.

I believe if :system.form_status != 'QUERY' you'll need to loop through through the blocks checking :system.block_status to see who changed. Of course you'd have to go_block() before checking the status.

How we will know that dimension size is more than the fact table size?

how we will know that dimension size is more than the fact table size?

Hi,
Let us assume that we are going to take Division and distribution channel in a dimension and assume we have 20 distinct values for Division in R/3 and 30 Distinct values for Distribution channel .So Maximum, we can get 20 * 30 records in dimension table and we can take rough estimation of records in the cube by observing the raw data in source system.
With rgds,
Anil Kumar Sharma .P

How to change existing database block size in all tablespaces

Hi,
Need Help to change block size for my existing database which is in 8kb of block size.
I have read that we can only change block size during database creation, but i want to change it after database installation.
because for some reason i dont want to change the database installation script.
Can any one list the steps to change database block size for all existing table space (except system, temp ).
want to change it to 32kb.
Thank you for you time.
-Rushang Kansara

> We are facing more and more physical reads, I thought by using 32K block size
we would resolve that..
A physical read reported by Oracle may not be - it could well be a logical read from the o/s file system cache and not a true physical read. With raw devices for example, a physical I/O reported by Oracle is indeed one as there is no o/s cache for raw devices. So one needs to be careful how aone interprets number like physical reads.
Lots of physical reads may not necessarily be a bad thing. In contrast, a high percentage of "good/fast" logical reads (i.e. a high % buffer cache hit ratio) may indicate a serious problem with application design - as the application is churning through the exact same data again and again and again. Applications should typically only make a single pass through a data set.
The best way to deal with physical reads is to make them less. Simple example. A database deals with a lot of inserts. Some bright developer decided to over-index a table. Numerous indexes for the same columns exist in difference physical column orders.
Oracle now spends a lot of time dealing (reading) with these indexes when inserting (or updating a row). A single write I/O may incur a 100 read I/Os as a result of these indexes needing to be maintained.
The bottom line is that "more and more physical I/O" is merely a symptom of a problem. Trying to speed these up could well be a wasted exercise. Besides, the most optimal approach to "lots of I/O" is to tune it to make less I/O.
I/O is the most expensive operation for a RDBMS. It is very difficult to make this expense less (i.e. make I/Os faster). It is more effective to make sure that you use this expensive resource in an optimal way.
Simple example. Single very large table with 4 indexes. Not very efficient design I/O wise. Single very large partitioned table with local indexes. This can reduce I/O on that table by up to 80% in my experience.

How do you know what frame size to make your movie?

Hello everyone,
I know this is probably an easy question, but I just need someone to sum it up for me
If I'm going to compress my movie (Shot in 4:3, 720x480) and I want to put it on someone else website... which I don't know there frame size... like youtube, can I just submit any size and their website will fit it for me?
Does that make sense?
Like I know youtube says you can submit a file size of up to 1 gb, but what frame size should it be? Or do I just make the best looking movie I can from compressor and then just submit?
Thanks...

Most sites such as YouTube will resize it for you, yes. For specific YouTube encoding, this may be of assistance:
http://www.kenstone.net/fcphomepage/you_tube_reduxgary.html

How to Calculate the Database block size??

Can someone please tell me how during the Oracle Installation does one calculate the db_dblock_size. Thank u

One way to find is to right click the drive in Windows Explorer and click Format (Not actually formatting it).
In the popup window, you would see the "Allocation unit size" for the selected drive. Click "Close" to exit when done.

Error Message Said to Use Dual-Layer Disc - How Can I Know the File Size?

This is my first attempt at using iMovie. I used slides, added a music and speaking track over it.
I would like to reduce the size to a standard DVD rather than using expensive dual-layer discs. How do I determine the size?
My Mac is only 80 GB, is that a problem?
Thanks,
Carlos Marques

It seems as if perhaps you've clicked, in iMovie, on 'File' and 'Burn Project to Disc...' instead of Exporting to iDVD.
When you Export to iDVD, your project ought to easily fit on a DVD.
But if you've chosen 'Burn Project to Disc...' that doesn't make a playable DVD ..it creates a backup data disc, and, as Fred suggests, if you're using large or detailed photos, that may need a lot of space ..much more than when using iDVD to make a playable video disc.
(..iDVD compresses everything so that anything up to one or two hours' worth will fit on a 4.7GB DVD, as Fred described. Burning a Project to a disc just copies all the data that's in your iMovie project without compressing anything; without converting hi-resolution photos to the low resolution of a movie. That may be why it's suggesting that you need a Dual-Layer disc if you did choose 'Burn Project to Disc...' by mistake..)

How can I know the total size of a playlist ?

I can't find anymore the size of a playlist in mb or gb. There are only the number of elements and the days but no more the actual size...
I tried to switched the presentation mode but I still cannot find it.

Thanks. That answers my question. It's jut not obvious that clicking at the header of the first column will restore the established sequence. Even if the listing is re-sorted by artist name or album title, the left column still lists as 1, 2, 3....25 instead of 18, 12, 5, 3... or whatever the different sorting has done to your desired track sequence. The behavior of the numbers in the column makes it look more like a simple track count. It would be nice if there was a "track count" column and a "play order" column whereby if you click on Copy To Play Order off the right click, the "play order" is renumbered to match the "track count" column according to however you currently have the tracks listed. Anyhow, question answered. Many thanks!

How do i know the entire size of the schema

I want to ask how to use sqlplus to find out how big it the entire schema in oracle?
please provide the sql statement.

hi,
use this query as aconnected user and use dba_segments as sydba privilege
SQL> select tablespace_name,sum(bytes/1024/1024/1024) from user_segments where tablespace_name='USERS'group by tablespace;
to find tablespace details
select * from user_ts_quotas;
select tablespace_name,sum(bytes/1024/1024/1024) from user_ts_quotas group by tablespace_name;
regards,
Deepak

How to know the OS block size ?

Hi all
I want to know how to get the OS block size of my server ?
For example if my server is Windows 2000 Professionnal , how can I get the size of my OS block size ?
Thank you

One way to find is to right click the drive in Windows Explorer and click Format (Not actually formatting it).
In the popup window, you would see the "Allocation unit size" for the selected drive. Click "Close" to exit when done.

How to find block size in OS

I know db_block_size and db_file_multiblock_read_count of Oracle should be multiple of OS(operationg System).
Can anybody suggest me , how can i find out block size in window or Linux.
Thanks in advance
Tinku

$show parameter db_block_size this is the setting from your init.ora file.
This parameter is set at the database creation time and cannot be altered.
In linux system use
dumpe2fs -fh /dev/hdb
to get information about your block size.
In my case it was 4k so my db_block_size will be multiples of 4k.
http://www.dizwell.com/html/db_block_size.html
Thanks
Gopal
visit
http://dba.shilpatech.com/

How can we know the size of the dimension(in Line item Dim)?

Hi to all experts,
We use Line item dimension if the size of dimension is 20% or more of the fact table. My doubt is that how can v know that the size of the dimesion is 20% or more of FT?. But we never store MD in dimension tables......So please help me to understand this scenario? Thanks in advance.

Hi
Normally before modelling you will assume the number of entries in your master data and transactional data..
If your dimension is having 3 characteristics
say A,B .....and these characteristic values are say
A---10,000( Total number of master data records)
B----7,000( Total number of master data records)
then your dimenstion would be 10,000 * 7,000 =700000000
in this case you better keep A in a dimension and B in another dimension.
Normally SAP recommends your dimension table shouldnot exceed 100,000...
so whenever you expect a characteristic is having more values then you should make it as line item...
If you want to add a new characteristic to the existing model then you can decide by comparing the ratio of dimension table to the fact table..
Please have a look at the below url for sizes
dimension size
Hope it helps
Thanks,
Teja
Edited by: Teja badugu on Apr 24, 2008 12:19 PM

How get os physical block size ?

man dd, it advice bs parameter be a multiple of the physical block size .
How can I get physical block size ? such as aix, hpux ,suselinux.
bs=BlockSize
Specifies both the input and output block size, superseding the ibs and obs flags. The block size values
specified with the bs flag must always be a multiple of the physical block size for the media being used.

Learning new things today, thanks guys!
$ printf "a" >1bytefile.txt && echo $(( 512 * $(du 1bytefile.txt | cut -f1) )) && rm 1bytefile.txt
1024
$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.4.0 - Production on Tue Jul 24 16:15:04 2012
Copyright (c) 1982, 2007, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SYS@TTST> select
2    max(l.lebsz) log_block_size
3 from
4    sys.x$kccle l
5 where
6    l.inst_id = userenv('Instance');
LOG_BLOCK_SIZE
          1024
SYS@TTST> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
$ /usr/sbin/fstyp -v /dev/vg01/lvol04
/dev/vg01/lvol04: Permission denied
$ su
Password:
# /usr/sbin/fstyp -v /dev/vg01/lvol04
vxfs
version: 5
f_bsize: 8192
f_frsize: 1024
f_blocks: 786432000
f_bfree: 87190098
f_bavail: 81740717
f_files: 22035604
f_ffree: 21797524
f_favail: 21797524
f_fsid: 1073807364
f_basetype: vxfs
f_namemax: 254
f_magic: a501fcf5
f_featurebits: 0
f_flag: 16
f_fsindex: 10
f_size: 786432000
# uname -r
B.11.23
# uname
HP-UXMore info over in the hp communities.

Finding appropriate block size?

Hi All,
I believe this might be basic question, How to find appropriate block size for building an database to an specific application?
I had seen always default 8K block size is used every where(Around 300-350 databases i have seen till now)....but why and how do they estimate this block size blindly before creating production database.
Also in the same way how memory settings are finalized before creating database?
-Yasser

Yasser,
I have been very fortunate to buy and read several very high quality Oracle books which not only correctly state the way something works, but also manage to provide a logical, reasoned explanation for why things happen as they do, when it is appropriate, and when it is not. While not the first book I read on the topic of Oracle, the book “Oracle Performance Tuning 101” by Gaja Vaidyanatha marked the start of logical reasoning in performance tuning exercises for me. A couple years later I learned that Gaja was a member of the Oaktable Network. I read the book “Expert Oracle One on One” by Tom Kyte and was impressed with the test cases presented in the book which help readers understand the logic of why Oracle behaves as it does, and I also enjoyed the performance tuning stories in the book. A couple years later I found Tom Kyte’s “Expert Oracle Database Architecture” book at a book store and bought it without a second thought; some repetition from his previous book, fewer performance tuning storing, but a lot of great, logically reasoned information. A couple years later I learned that Tom was a member of the Oaktable Network. I read the book “Optimizing Oracle Performance” by Cary Millsap, a book that once again marked a distinct turning point in the method I used for performance tuning – the logic made all of the book easy to understand. A couple years later I learned that Cary was a member of the Oaktable Network. I read the book “Cost-Based Oracle Fundamentals” by Jonathan Lewis, a book by its title seemed to be too much of a beginner’s book until I read the review by Tom Kyte. Needless to say, the book also marked a turning point in the way I approach problem solving through logical reasoning, asking and answering the question – “What is Oracle thinking”. Jonathan is a member of the Oaktable Network, a pattern is starting to develop here. At this point I started looking for anything written in book or blog form by members of the Oaktable Network. I found Richard Foote’s blog, which some how managed to make Oracle indexes interesting for me - probably through the use of logic and test cases which allowed me to reproduce what I reading about. I found Jonathan Lewis’ blog, which covers so many interesting topics about Oracle, all of which leverage logical approaches to help understanding. I also found the blogs of Kevin Closson, Greg Rahn, Tanel Poder, and a number of other members of the Oaktable Network. The draw to the performance tuning side of Oracle administration was primarily for a search for the elusive condition known as Compulsive Tuning Disorder, which was coined in the book written by Gaja. There were, of course, many other books which contributed to my knowledge – I reviewed at least 8 of the Oracle related books on the amazon.com website.
Motivation… it is interesting to read what people write about Oracle. Sometimes what is written directly contradicts what one knows about Oracle. In such cases, it may be a fun exercise to determine if what was written is correct (and why it is logically correct), or why it is wrong (and why it is logically incorrect). Take, for example, the “Top 5 Timed Events” seen in this book (no, I have not read this book, I bumped into it a couple times when performing Google searches):
http://books.google.com/books?id=bxHDtttb0ZAC&pg=PA17#v=onepage&q=&f=false
The text of the book states that the “Top 5 Timed Events” shown indicates a CPU Constrained Database (side note: if a database is a series of files stored physically on a disk, can it ever be CPU constrained?). From the “Top 5 Timed Events”, we see that there were 4,851 waits on the CPU for a total time of 4,042 seconds, and this represented 55.76% of the wait time. Someone reading the book might be left thinking one of:
* “That obviously means that the CPU is overwhelmed!”
* “Wow 4,851 wait events on the CPU, that sure is a lot!”
* “Wow wait events on the CPU, I didn’t know that was possible?”
* “Hey, something is wrong with this ‘Top 5 Timed Events’ output as Oracle never reports the number of waits on CPU.”
* “Something is really wrong with this ‘Top 5 Timed Events’ output as we do not know the number of CPUs in the server (what if there are 32 CPUs), the time range of the statics, and why the average time for a single block read is more than a second!”
A Google search then might take place to determine if anyone else reports the number of waits for the CPU in an Oracle instance:
http://www.google.com/search?num=100&q=Event+Waits+Time+CPU+time+4%2C851+4%2C042
So, it must be correct… or is it? What does the documentation show?
Another page from the same book:
http://books.google.com/books?id=bxHDtttb0ZAC&pg=PA28#v=onepage&q=&f=false
Shows the command:
alter system set optimizer_index_cost_adj=20 scope = pfile;Someone reading the book might be left thinking one of:
* That looks like an easy to implement solution.
* I thought that it was only possible to alter parameters in the spfile with an ALTER SYSTEM command, neat.
* That command will never execute, and should return an “ORA-00922: missing or invalid option” error.
* Why would the author suggest a value of 20 for OPTIMIZER_INDEX_COST_ADJ and not 1, 5, 10, 12, 50, or 100? Are there any side effects? Why isn’t the author recommending the use of system (CPU) statistics to correct the cost of full table scans?
A Google search finds this book (I have not read this book either, just bumped into it during a search) by a different author which also shows that it is possible to alter the pfile through an ALTER SYSTEM command:
http://books.google.com/books?id=ufz5-hXw2_UC&pg=PA158#v=onepage&q=&f=false
So, it must be correct… or is it? What does the documentation show?
Regarding the question of updating my knowledge, I read a lot of books on a wide range of subjects including Oracle, programming, Windows and Linux administration, ERP systems, Microsoft Exchange, telephone systems, etc. I also try to follow Oracle blogs and answer questions in this and other forums (there are a lot of very smart people out there contributing to forums, and I feel fortunate to learn from those people). As long as the book or blog offers logical reasoning, it is fairly easy to tie new material into one’s pre-existing knowledge.
Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc.

How do I know disk block size of OS?

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