- Community Home
- >
- Servers and Operating Systems
- >
- Operating Systems
- >
- Operating System - HP-UX
- >
- Re: reducing raw volume
Categories
Company
Local Language
Forums
Discussions
Forums
- Data Protection and Retention
- Entry Storage Systems
- Legacy
- Midrange and Enterprise Storage
- Storage Networking
- HPE Nimble Storage
Discussions
Discussions
Discussions
Forums
Forums
Discussions
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
- BladeSystem Infrastructure and Application Solutions
- Appliance Servers
- Alpha Servers
- BackOffice Products
- Internet Products
- HPE 9000 and HPE e3000 Servers
- Networking
- Netservers
- Secure OS Software for Linux
- Server Management (Insight Manager 7)
- Windows Server 2003
- Operating System - Tru64 Unix
- ProLiant Deployment and Provisioning
- Linux-Based Community / Regional
- Microsoft System Center Integration
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Community
Resources
Forums
Blogs
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-18-2010 03:58 AM
тАО02-18-2010 03:58 AM
can i do a lvreduce on raw database file..
Actaully i want to shrink a database raw file rxxx.dbf
I have heard the lvreduce will destroy all data on any LV.
<<< LVM does not store any information about which physical extents within a logical volume contain useful data; therefore, reducing the space allocated to a logical volume without doing a prior backup of the data could lead to the loss of useful data"
If you lvreduce a LVOL you "delete" the data on this disk. >>>
As per my understanding,
1. In raw device file data will be written serially that means data will be written continously with no gap in between.So we can do lvreduce without data loss.
2.In LV wich holds file system,data will be written randomly.So doing a lvreduce here is not recommended.
Please suggest on this.
Solved! Go to Solution.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-18-2010 04:18 AM
тАО02-18-2010 04:18 AM
Re: reducing raw volume
To find out what applications are using the logical volume, use the fuser command
Example:
fuser -cu /dev/vg01/lvol5
IF any application/user is accessing this file system,you may stop that applciation before resuce this LV.
You can reduce that lv but new size of lv should be higher than data already occufied on LV.
Before reducing the lv,better take data backup.
example.
total lv size 5GB
data occufied 3.5GB
you want to reduce that lv to 4.5GB,it is possible.use lvreduce -L
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-18-2010 04:38 AM
тАО02-18-2010 04:38 AM
Solutiondirect from the Oracle buffer cache to the disk
More over "Logical volumes can be assigned to
file systems,
used as swap or dump devices,
or used for raw access
so when you talk about "raw device files" its totlay raw -> nothing stored "while all you Database / Application has been stopped"
make sure "NO I/O activity " (meaning make sure all your Database & application complted down) and you do this activity.
You can use either "use" lvreduce or
"lvremove " and "lvcreate" to actual size.what do you " and inform your " DBA admin", can help you reconfugre or something drop and recreat .etc.. (whatever from Databse point of view).
HTH,
Johnson
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-18-2010 04:51 AM
тАО02-18-2010 04:51 AM
Re: reducing raw volume
>>so when you talk about "raw device files" its totlay raw -> nothing stored "while all you Database / Application has been stopped>>
So you are telling when DB is down raw database file will be empty.This is new thing to me.
So where data will be stored while DB is down.
Please clarify
Regards
himacs
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-18-2010 06:36 AM
тАО02-18-2010 06:36 AM
Re: reducing raw volume
Please read document for "Better understanding" for raw device use in Oracle Database.
http://www.rdbconsulting.com/files/Raw%20devices%20versus%20file%20systems%20v2.pdf
>>So where data will be stored while DB is down.<<
Again read post " since a write to a raw device bypasses the UNIX buffer cache;"
So it use "bypasse" to "when you database is up data "bypasses. no data is stored.
purpose of having raw devic file "
Improves I/O performance if system is I/O bound
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-20-2010 08:34 PM
тАО02-20-2010 08:34 PM
Re: reducing raw volume
Thanks for the document.I have logged a call with HP to confirm the same.But according to them we can reduce the raw device.
<< first tell Oracle to shrink
the tablespace, and then you can go ahead and shrink the LV. The LV operations can be done online. Make
sure you do not shrink the LV by a larger space than you shrunk the tablespace in Oracle, or data will be lost
with no way to recover it! >>
Regards
himacs
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-20-2010 09:31 PM
тАО02-20-2010 09:31 PM
Re: reducing raw volume
Yes, Please, d'not shrink too much. also can you check whether is better you "lvremove" & "lvcreate" ? hence from system point of view its straight forward. (meant say all "Lv operations can be done") from Oracle point view check with your "DBA Admin"
Just a thought.
Thanks,
Johnson