Is my OS block size 4096 or 512 bytes?

Hi!
I am working on RHEL 4.5 ES edition. I have an installation of an Oracle 10g database whose files spread out over two separate partitions /u01 and /u02 that show a block size of 4096 using dumpe2fs.
dumpe2fs /dev/sdb1 | grep 'size'
dumpe2fs /dev/sda7 | grep 'size'
Block size: 4096
Fragment size: 4096
Inode size: 128
Using a different method of deriving the OS block size by querying v$archived_log I get the output of 512.
Is the v$archived_log method of finding the OS block size incorrect?
Thanks and Regards,
Aniruddha

What does
/sbin/tune2fs -l /dev/xxx
return? 4096 only? If yes, then your block size is 4096.
From http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/dynviews_1016.htm#sthref3455
The online log logical block size is a platform-specific value that is not adjustable by the user.
So may be it is fixed at 512 bytes.
Others: Please comment.

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Database block size vs. tablespace blocksize

dear colleques
the block size of my database is 8192 (db_block_size=8192), all the tablespace that i have, have the same block size, now i want to create a new tablespace with a different block size, and when i do so i receive the following error
ORA-29339: tablespace block size 4096 does not match configured block size
please help solving the problems
cheers
asif

$ oerr ora 29339
29339, 00000, "tablespace block size %s does not match configured block sizes"
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OS block size

Hi
How to check OS block size in LINUX and Windows.
Regards

But as a oracle dba one should know how to find/know the os block size to set proper value for the
db_block_size oracle initialization parameter.http://www.lmgtfy.com/?q=ext3+block+size
Once you know OS block size, what formula is used "to set proper value for the db_block_size oracle initialization parameter"?
bcm@bcm-laptop:~$ sudo tune2fs -l /dev/sda1 | grep -i 'block size'
[sudo] password for bcm:
Block size: 4096
Edited by: sb92075 on Dec 19, 2009 8:41 PM

How to find block size of my OS

Hi I am using redhat 9, I would like to know how to find out my OS block size as I need to give the database block size accordingly...

I would rather adjust the OS block size to required database block size, not vice versa if possible.
You can check the FILESYSTEM block size using dumpe2fs command (replace /dev/sda5 with your filesystem blocks device):
[root@localhost ~]# dumpe2fs /dev/sda5 | grep "Block size"
dumpe2fs 1.39 (29-May-2006)
Block size: 4096
If you want to know what's the minimum OS block device IO block size (which is not the same thing as filesystem block size), you can do it easily using an Oracle command (if your db is in archivelog mode):
select block_size from v$archived_log where rownum = 1;
Tanel.
http://blog.tanelpoder.com

What USB storage devices have a block size of 512 bytes?

After pulling my hair out for weeks trying to get a usb hard drive to work with my new AirPort Extreme (802.11n), I ran across this
http://docs.info.apple.com/article.html?artnum=305038
AirPort Extreme (802.11n): USB storage device supported formats and protocols
You can connect USB-based storage devices to an AirPort Extreme (802.11n). Learn which formats and protocols are supported.
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Now, this information is not easily obtainable while
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Would have bee nice to know that not all usb hard drives
are supported by the AirPort Extreme (802.11n) before I
purchased it.
Thanks
J Riley

Duane posted a link to an unofficial 802.11n Airport Extreme Hard Drive Compatibility List.
http://www.ifelix.co.uk/tech/8014.html
Still not enough information to make an informed purchase that
will work.

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Hi ebrian,
You can't perform a migration from Linux to Windows in that manner with 9i.The plan can be changed to migrate from 9.2.0.4 to 10g and than move from 32-bit Linux to 32-bit Windows.
It should not matter the end result for the OP is the same 10g on 32 bit windows.
It just depends on what technoly the OP wants to use (export/import or rman convert).
Regards,
Tycho

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OSD-04001: invalid logical block size (OS 2800189884)

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Hi Zulqarnain,
Error OSD-04001 is Windows NT specific Oracle message. It means that the logical block size is not a multiple of 512 bytes, or it is too large.
So what you can do? Well you should try to change the value of DB_BLOCK_SIZE in the initialization parameter file.
Regards

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Is there a way to change the default block size on the tftp server so that it defaults to 1024 instead of 512
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Go to Solution.
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data from DAQcard.PNG ‏95 KB

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I'm planning to setup a raid0 with 2x 2TB HDD's to store and edit the videos from my digital camera on it. The most files will have a size of 5 to 15GB. In the past i had raid0's on RHEL with the (old) default stripe block size of 64kb. Since the new drive will only contain very big files would it be better to go with 512kb stripe block size ? 512 is also the default setting now in the gnome disk utility which i use for my partitions.
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That is a hard question to answer.. Nothing is best for everyone... However if i am to generalize it I would put it this way.. If you want to cut everything from a short promos to hollywood pictures..
A high end windows pc (only cause mac pro hasn't been updated in ages)
Avid Media Composer with Nitrus DX
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You are looking at over 70,000 or 80,000, could even approach even more.. HD decks run atleast 15k.
If price is not an issue then there you go....
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I am a final cut child who grew up on it and love it however everything I am doing in last few years is on AVID...
Have a second monitor..
I am very portable and rest of the gear I usually get where ever I work at.. I am looking into getting a good broadcast monitor connected with AJA thunderbolt..
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Be more specific and you will get clearer answers..

ORA-00374 - Block Size issue

I've already searched and researched this quite a bit. I am not using 9i like the other post about this issue from many years ago. Before you ask "Why a db_block_size of 32k?", this is for a test case. Simple as that.
My system:
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Windows Server 2008 R2 Standard 64bit (I much prefer Linux, but this test requires Win2008)
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Total Clusters : 0x0000000000e5ff1f
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Windows DOES support up to a 64k allocation size. Does anyone know why Oracle is giving me a hard time about it?
I saw Metalink note 794842.1, but I'd like to know the reasoning/logic for this limitation?
Edited by: user6517483 on Jun 24, 2010 9:21 PM

user6517483 wrote:
I saw Metalink note 794842.1, but I'd like to know the reasoning/logic for this limitation?
A WAG.. Oracle is written to be run on a wide variety of operating system. As operating systems differ one typically designs something that is equivalent in functionality to a Windows HAL - this provides an abstraction layer between the kernel services/calls that is needed by the s/w and the actual implementation of such by the kernel itself.
So despite the kernel supporting feature X, it could be different than similar features supported on other kernels and difficult to implement via this s/w HAL-like interface. The Windows kernel has a lot of differences from the Linux kernel for example.. and somehow Oracle needs to make the same core db s/w run on both. Not unrealistic to expect that some kernel features will be supported better than others, as there is a common denominator ito design and implementation in the core s/w.
As this is a case with block sizes... not that critical IMO. I have played with different block sizes in a 20+TB storage system and Oracle RAC (10.2g) on Linux (part of testing the combo of storage system and cluster and technologies used). Larger block sizes made zero difference to raw I/O performance. The impact was instead more a logical one. Fewer db blocks can be cached as these are larger.. more data can be written into a datablock. And as numerous experienced Oracle professionals have commented, Oracle decided that the default 8KB size is a best fit at this layer.
So extensive and very accurate testing needs to be done IMO to determine whether a larger block size is justified... and the effort to do that may just outweigh the little gains achieved by finding the "+perfect+" block size. Why not focus all that effort instead on correctly using Oracle? Application design? Data modeling? Development and coding? These are factors that play the most dominant roles at the end of day that impact and determine performance.

Increasing TFTP block size for 2960 series switches

I have read that some Cisco components can increase the default TFTP block size to values greater than 512 bytes by using the command -
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I have moved a WS-C2960-24LC-S running LanLite to 12.2(55)SE9 - the current end of the line for this switch - and indeed the command is not present. Sooo....this appears to be a limitation of LanLite.
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Is my OS block size 4096 or 512 bytes?

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