Database, RAC | Data Guard, Virtualization

VMWare: Adding Shared Disks for Clustered Oracle Database

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Hi folks!
Today a friend asked about how to configure disks on VMWare to create a virtualized cluster database. I revisited my old notes and decided to share. Here it goes…

First, I really have some constraints about it:
– Fake “high availability”: To have HA with VM it’s not needed 2 vms, if a host fail VMWare should make a VMotion (if well configured), and no services will be affected. So, one VM is ok.
– Not real “horizontally scallated”: It probably would be better to use one server as physical than have two vms on it. Not make sense to do it…

So, why?
To prove concept, evaluate RAC configuration (caches on sequences, etc) and labs, to learn and practice RAC stuffs…

Ok, now how to make it happen?

1. Add new disk to one of the machines. Some way, one will be the “primary” and share disks with another.
add1.jpg

2. Set Mode Thick Eager Zeroed

add2.jpg

3. Create a specific controller to this “shared disks”

add3.jpg

4. Set controller to virtual sharing

add4.jpg

# Other Machine
5. Adding the existent disk to other VM (not primary, but from primary)

add5.jpg
6. Select disk from primary

add6.jpg

add7.jpg

7. Create a new controller, as you made on primary and select it:

add8.jpgadd9.jpg

8. Set controller to virtual sharing
add10

OBS:
If this error happen, one of your controller is not in sharing mode. Please check it.
add11

 

And here we are! 🙂
Good lab!
Matheus.

Linux, Shell Scripts

Linux: Resizing Swap Online

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Hi all!
Quick one to resize swap online:

[root@server-db ~]# swapon -s
Filename                                Type            Size    Used    Priority
/dev/mapper/rootvg-lvswap              partition       5242872 373624  -1
[root@server-db ~]# vgs
VG                #PV #LV #SN Attr   VSize   VFree
[...]
rootvg              1   6   0 wz--n- 135.69G 5.69G
[...]
[root@server-db ~]# lvextend -L +2048M /dev/mapper/rootvg-lvswap
Extending logical volume lvswap to 7.00 GB
Logical volume lvswap successfully resized
[root@server-db ~]# vgs
VG                #PV #LV #SN Attr   VSize   VFree
[...]
rootvg              1   6   0 wz--n- 135.69G 3.69G
[...]
[root@server-db ~]# mkswap /dev/mapper/rootvg-lvswap
Setting up swapspace version 1, size = 7516188 kB
[root@server-db ~]# swapoff /dev/mapper/rootvg-lvswap
[root@server-db ~]# swapon /dev/mapper/rootvg-lvswap
[root@server-db ~]# swapon -s
Filename                                Type            Size    Used    Priority
/dev/mapper/rootvg-lvswap              partition       7516188 373624  -1

See ya!
Matheus.

Database, Errors and Bugs, MySQL

MySQL: Unable to connect to database ‘xxx’ on server ‘xxx’ on port xx with user ‘root’

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Quick tip:

# Problem:

MySQL: Unable to connect to database 'xxx' on server 'xxx' on port xx with user 'root' - Access denied for user 'root'@'xxxxx'

 

Solution:

GRANT ALL PRIVILEGES ON *.* TO root@'xxxxx' IDENTIFIED BY '$PASSWORD' WITH GRANT OPTION;
FLUSH PRIVILEGES;

 

Have a nice week!
Matheus.

Backup and Restore, Database

Transporting 12TB Database Over 4.000 km with EMC DDomain

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Hi all!
I’m here to share this is great whitepaper by EMC about Transporting a 12 TB Oracle Database almost 4.000km using Data Domain to Backup and restore.

DDTransportation
Take a look:
https://www.emc.com/collateral/software/white-papers/h8238-oracle-remote-recovery-datadomain-wp.pdf

It’s nice to see how deduplication was a key-factor to the success of project.
It’s really a good feature that provides lots of optimization to backup/recover databases, besides diskspace saving, backup window reducing, network interface load reducing, etc.

Have a nice weekend!

Database, Enterprise Manager, MySQL

Monitoring MySQL with Nagios – Quick View

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Hi all!
As you know, we have some commercial solutions to monitoring/alerting MySQL, like MySQL Enterprise Monitor or Oracle Grid/Cloud Control.

But, regarding we are using MySQL instead of Oracle Database, we can assume it’s probably a decision taken based on cost. So, considering Open Source solutions, we basically have Nagios, Zabbix, OpenNMS…

MangagedMonitoringConsole

 

Thinking on Nagios, in my opinion the “supra sumo” is mysql_health_check.pl.
Below whitepaper and presentation:
White Paper
Presentation
Code
Good one by Sheeri Cabral and posted here!

Any way, with theese two we can make lots of magic:

1. check_mysql.pl
– Check status of MySql server (slow queries, etc)
– Queries per second graph

2. check_db_query.pl
– Allowes to run SQL Queries and setting thresholds for warning e critical. Ex:

check_db_query.pl -d database -q query [-w warn] [-c crit] [-C conn_file] [-p placeholder]

Ex for Nagios call:

define command{
command_name    check_db_entries
command_line    /usr/local/bin/perl $USER1$/check_db_query.pl -d "$ARG1$" -q "$ARG2$" $ARG3$
}

So, now it’s just make your queries and implement your free monitoring on MySQL! 🙂
Matheus.

Database, SQL | PLSQL

Alter (Fix) Oracle Database Date

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When you haven’t access to SO and just have to alter database date…

# Fix Date:

ALTER SYSTEM SET fixed_date = '2016-04-05-12:00:00';

# Unfix Date:

ALTER SYSTEM SET fixed_date = NONE;

 

OBS: Just to make it clear: The date will be really “fixed”. The time will “stop”. Seconds, minutes will not advance…
Matheus.

Backup and Restore, Database, MySQL, PostgreSQL, Shell Scripts, Tools

Export/Backup directly to Zip using MKNOD!

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We all faced that situation when we have to make a logical backup/export and haven’t so much area to do that, right?
We know the export usually compress a lot on zip/gzip… It wouldn’t be great if we can export directly to compressed file?

zip
This situation become much more common because of Datapump, that requires a directory accessible by database server. If you have not possibility to make a mounting point or any other area, this can help…

## BKP with MKNOD
BKP_DEST=/just/example
DATE=`date +%Y%m%d%H%M`
cd $BKP_DEST
mknod bkp_$DATE.dmp p
gzip  bkp_$DATE.dmp.gz &
### Uncomment and Ajust one of:
## MySQL:
#mysqldump -u $user -p$password $database > bkp_$DATE.dmp
## Oracle (Datapump or EXP)
expdp \"/ as sysdba\" dumpfile=bkp_$DATE.dmp full=y directory=DIRECTORY_EXAMPLE logfile=log_bkpzipped.log compress=y
#expdp $user/$password dumpfile=bkp_$DATE.dmp full=y directory=DIRECTORY_EXAMPLE logfile=log_bkpzipped.log
#exp \"/ as sysdba\" file=bkp_$DATE.dmp log=log_bkpzipped.log compress=y [tables=owner.table,..] [owner=schema1,..] [...]

Hugs!
Matheus.

Linux, Shell Scripts

Linux Basic: Creating a Filesystem

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From disk to filesystem:

> Rescan on scisi controller to detect the disk (controller id 0, in  this example)

echo "- - -" > /sys/class/scsi_host/host0/scan

– List disks

fdisk -l

> Fdisk choosing options n -> new p->partition 1-> partition number

fdisk /dev/sdm

> Create physcal volume

pvcreate /dev/sdm1

> Create Volume Group

vgcreate oracle /dev/sdb1

> Rename Volume Group

vgrename oracle vgoracle

> Create LV

lvcreate -L 19G -n lvoracle vgoracle

> Extend LV

lvextend -L +990M /dev/vgoracle/lvoracle

> Make FileSystem

mkfs.ext3 -m 0 -v /dev/vgoracle/lvoracle

OBS: m 0 is the journal (for recovery in case of crash).  “0” because I don’t want it now. So, 100% of disco will be available for using on fs.

> Mount filesystem on Directory

mount -t ext3 /dev/vgoracle/lvoracle /oracle/

> Just to check:

$ df -h
/dev/mapper/vgoracle-lvoracle
20G  173M   20G   1% /oracle

 

Have a nice day!
Matheus.

Database, Errors and Bugs, Shell Scripts

Tip for the Future: Segmentation fault because of LD_LIBRARY_PATH

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More than once I forgot to set LD_LIBRARY_PATH in new environments and sometimes I faced awkward errors. The most common is “Segmentation Fault”.
Today a lost almost 15 minutes searching about Segmentation Fault related to Datapump on 11.2, then I realized I forgot the LD_LIBRARY_PATH again…

Other day, in a Upgrade from 11.2.0.3.6 to 11.2.0.4.2 I get stuck in lots of errors on upgrade process. Bullshit again, after a few minutes of errors and searching I founded a post, somewhere, talking about the variables setting.

So, Matheus from the Future: Check if LB_LIBRARY_PATH and other variables are setted for the right Oracle Home.

I expect this post save me from this same pain in the future. 😛
Thanks.

Matheus.