Autonomous Linux – Did you hear about it?

Hi all!

Not long ago Oracle lunched the Oracle Autonomous Database which run from the Oracle Cloud Infrastructure. This new service provides a database which several tasks are automated for you. From security patching, performance tunning and others…

ccac4eed66edabdb4b94b7aa54071ba8

So what this is all about?

Now the Oracle Linux was added to the Autonomous family as well. This means it is an operation system which runs from OCI which goals are to provide a more secure, cost effective and high reliable system with less manual administrative tasks.

It’s not new that security patches are a must but who has the downtime avaliable or the staff to patch their systems every time a new patch is released?

With Oracle Ksplice you will have kernel patches without having to reboot your instance. zero-day vulnerabilities and overall reduced sys admin manual tasks. But we know that this type of solutions do not replace a professional but insetad free their time to do other more important tasks.

What are the down sides of it? In my humble opinion is that we dont have much option to deny a update once we have it automated. We can use the Oracle OS Management Service to manage the servers separating which we want to automate or to manual control.

Note from the Autonomous Linux page is that The Oracle Autonomous Linux image has been moved. It will no longer be available on the  Oracle Cloud Marketplace or the Oracle Images catalog. As of this date, it is available from the Platform Images catalog within the Oracle Cloud Infrastructure console, when creating a compute instance.

I got my seft locked out my OCI account (while studying for the free exams, if dont know what I´m talking abuot please see it here) so I wont be able to show scrren on how to create a insatnce useing the Autonomous Linux but for sure this will be done very soon.

Stay sharp!

Elisson Almeida

Checking Basic Licensing Info on a DB Server

Hi all!
So, I got a new client and started checking on his licensing and hardware. Then I realized how “non-standard” this is and Oracle should probably provide a better way to do it. So I decided to share a few things:

# Checking Oracle Version Installed:

[oracle@greporaSRV inventory]$ cd /opt/oraInventory/logs
[oracle@greporaSRV logs]$  grep "\- Database edition" installActions*.log
INFO: - Database edition : Standard Edition One (Create and configure a database)

# Checking number of Sockets

[root@greporaSRV ~]# cat /proc/cpuinfo | grep "physical id" | sort -u | wc -l
1

# Checking number of CPU Cores per Socket

[root@greporaSRV ~]# lscpu | grep 'socket'
Core(s) per socket:    4

Parallel file transfer on Linux

Hi all,

I had a request to copy a ton of files from one file system to another,  I know that there are tools that can help with that like rsync but due to some requirements and me wanted to do some scripting I put something together  to help with this request. This is not the 1st time I do something like this but it is the 1st time I share 🙂

What I’m sharing is now what I did for the request I mentioned but you will get an idea

The script will copy a list of files from one server to another. This list I usually create by using find like this

find /Directory_which_I_want_to_copy -type f > file_list.txt

The script will receive some parameters as listed below

parallel_xfer.ksh    

Also a requirement for this to work is that you can ssh to the target server without a password.

It will keep X parallel sessions running at all times until there are new files to start copying it, After all copies are started, it will monitor them until completion. Also the script assumes that the source and target directory destination is the same but this is easily changed if needed.

The logging needs to be improved but it will show the file it started as well their processes count

Hope it helps

Elisson

#!/bin/ksh
DBLIST=${1}
DEST_DIR=${2}
SERVER=${3}
NUM_SESS=${4}
STARTED_COUNT=0
RUN_COUNT=0

trim() {
    local var=$@
    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
    echo "$var"
}


FILE_COUNT="$(cat ${DEST_DIR}/$DBLIST | wc -l)"
cd ${DEST_DIR}
for FILE in $(cat $DBLIST)
do
 STARTED_COUNT=$((${STARTED_COUNT}+1))
 if [ ${RUN_COUNT} -le ${NUM_SESS} ]
 then
   sftp -Cq USER@${SERVER}:${FILE} ${DEST_DIR}/. >/dev/null 2>/dev/null &
   echo "`date` - Transferring file ${FILE} to ${DEST_DIR} - ${STARTED_COUNT}/$(trim ${FILE_COUNT})"
   sleep 5
 fi
 echo "\n"

 RUN_COUNT=$(ps -ef | grep " ${$} " | grep sftp | grep -v grep | wc -l)

 while [ ${RUN_COUNT} -ge ${NUM_SESS} ]
 do
  RUN_COUNT=$(ps -ef | grep " ${$} " | grep sftp | grep -v grep | wc -l)
  echo "`date` - $(trim ${RUN_COUNT}) transfer processes running"
  echo "`date` - Amount of GB transferred `du -sg ${DEST_DIR}`\n"
  sleep 60
 done
done

while [ $(ps -ef | grep " ${$} " | grep sftp | grep -v grep | wc -l) -gt 0  ]
do
 RUN_COUNT=$(ps -ef | grep " ${$} " | grep sftp | grep -v grep | wc -l)
 echo "`date` - $(trim ${RUN_COUNT}) transfer processes running"
 echo "`date` - Amount of GB transferred - `du -sg ${DEST_DIR}`\n"
 sleep 60
done
echo "`date` - Transfered completed"

Installing EM 13c Agent on AIX 5.3

Hi,

Issues to install an Enterprise manager 13c agent on Database on AIX 5.3? Well, I found some errors I’d like to share with you:

First, to deploy agent manually by agentDeploy script, seems the ResponseFile is not working properly in some cases, so I recommend passing parameters manually:

./agentDeploy.sh AGENT_BASE_DIR = / u01 / app / oracle / agent13c -ignorePrereqs -invPtrLoc /etc/oraInst.loc AGENT_PORT = 3872 EM_UPLOAD_PORT = 4903 OMS_HOST =  ORACLE_HOSTNAME =  AGENT_INSTANCE_HOME = / u01 / app / oracle / agent13c / agent_inst AGENT_REGISTRATION_PASSWORD =  SCRATCHPATH = / backup / joao / temp

Al good? Not really, when starting the services, I started facing:

ERROR: Agent Configuration Failed SEVERE: emctl secure agent command failed with status = 1SEVERE: emctl secure agent command failed with status = 1SEVERE: emctl secure agent command failed with status = 1

Hmm… Why? So, seems this error is due to AIX secure with OMS (Linux). After a while, here is the workaround:

$ emctl secure agent -protocol TLS

That’s it! Try testing it now:

$ emctl upload agent

EMD upload completed successfully

Great! Agent installed. Now, to autodiscover further targets on host:

$ emctl config agent addinternaltargets

Now monitoring is complete!

[]s, Bicca.

OEM Metric “Memory Utilization” Different on 12c and 13c

So, as rollout strategy we created a new OEM13c to decommission a 12c. However during the testes, noticed Memory Utilization metric was a lot different between 12c and 13c. Why?

Happens that the Memory Utilization is calculated differently between 12c and 13c, but also seems 13c is more accurate, as per MOS The Host Memory Utilization Percentage Calculation in Enterprise Manager Cloud Control (Doc ID 1908853.1)

Well, those who are familiar with memory use computations in the operating system might become confused when examining the memory use metric data from Enterprise Manager 12c and 13c Cloud Control. Metrics such as Memory Utilization (%) do not have an equivalent in the OS, but OS data will be used in its derivation.

This is the formula used by Enterprise Manager 12.1.0.3 for Linux Memory Utilization (%), for example:

Memory Utilization (%) = (100.0 * (activeMem) / realMem)
 = 100 * 25046000/99060536
 = 25.28
EM Shows : 25.5

* On this, activeMem is Active Memory (Active), and realMem is Total Memory (MemTotal).

Comparing this with MemFree, which is not valid, might provide an impression that utilization is not being accurately represented.

Also, the “OEM13c value” was already collected in OEM12c, but under metric name “Used Logical Memory”. And basically “Memory Utilization” in 12c uses “activeMem” instead of “realMem-(freeMem+Buffers+Cached)”. As per image below.

OEM12_grep_mem

The formula in place on 13c is exactly the same as used to fix MOS EM 13c: Incorrect Memory Utilization Reported for Linux Hosts in Enterprise Manager 13.1.0.0.0 Cloud Control (Doc ID 2144976.1)

Example:

[root@greporasrv ~]# free
             total       used       free     shared    buffers     cached
Mem:     264087460  257669460    6418000    7657500     461088   11008128
-/+ buffers/cache:  246200244   17887216
Swap:     25165820    3365104   21800716

(100.0 * (realMem-(freeMem+Buffers+Cached)) / realMem)
100*(264087460-(6418000+461088+11008128))/264087460) = 93,22678328

As per OEM13c:

OEM13_grep_mem.jpg

Also, by checking on server using SAR, seems value in OEM 13c is more accurate, indeed:

[root@greporasrv ~]# sar -r
Linux 2.6.39-400.294.4.el6uek.x86_64 (greporasrv) 	08/29/2017 	_x86_64_	(44 CPU)

12:00:01 AM kbmemfree kbmemused  %memused kbbuffers  kbcached  kbcommit   %commit
12:10:01 AM   5377540 258709920     97.96    719080  10775828  83876744     29.00
12:20:01 AM   6131220 257956240     97.68    719504  10721084  82467712     28.51
12:30:01 AM   5623060 258464400     97.87    719700  10720972  83456216     28.85
12:40:01 AM   5606572 258480888     97.88    719836  10779108  83228440     28.77
12:50:01 AM   5783256 258304204     97.81    719860  10848644  82925908     28.67
01:00:01 AM   4151148 259936312     98.43    719888  11589048  84400040     29.18
01:10:01 AM   3717000 260370460     98.59    719904  11534336  84838784     29.33
01:20:01 AM   4282412 259805048     98.38    720164  11480792  84047568     29.06
01:30:01 AM   4473128 259614332     98.31    720184  11483604  83857348     28.99
01:40:01 AM   5113136 258974324     98.06    720256  11528492  83036284     28.71
01:50:01 AM   4971036 259116424     98.12    720284  11587956  82955128     28.68
02:00:01 AM   4026540 260060920     98.48    720344  11663184  86489692     29.90
02:10:01 AM   4312916 259774544     98.37    720380  11678316  83834592     28.98
02:20:01 AM   5058980 259028480     98.08    720408  11624028  82876972     28.65
02:30:01 AM   4609908 259477552     98.25    720556  11541392  83871244     29.00
02:40:01 AM   5020668 259066792     98.10    720592  11574912  82887808     28.66
02:50:01 AM   5175916 258911544     98.04    720748  11619572  82725252     28.60
03:00:01 AM   4701236 259386224     98.22    720780  11687100  83421624     28.84
03:10:01 AM   4757976 259329484     98.20    721204  11648864  83298716     28.80
03:20:01 AM   4485280 259602180     98.30    721248  11719272  83299472     28.80
03:30:01 AM   4267068 259820392     98.38    721264  11794688  83683344     28.93
03:40:01 AM   4080264 260007196     98.45    721404  11856796  83863540     28.99
03:50:01 AM   4864276 259223184     98.16    721676  11975372  82735744     28.60
04:00:01 AM   4427284 259660176     98.32    721696  12056676  83450524     28.85
04:10:01 AM   4868184 259219276     98.16    721736  11863420  82860464     28.65
04:20:01 AM   4711608 259375852     98.22    721760  11877192  83205684     28.77
04:30:01 AM   4452764 259634696     98.31    721928  11945108  83515596     28.87
04:40:01 AM   4800700 259286760     98.18    722072  12015444  82681320     28.58
04:50:01 AM   4796588 259290872     98.18    722212  12075496  82703948     28.59
05:00:01 AM   4320164 259767296     98.36    722372  12164956  83390596     28.83
05:10:01 AM   3350940 260736520     98.73    722488  12120116  84525028     29.22
05:20:01 AM   4200236 259887224     98.41    722628  11965996  83510580     28.87
05:30:01 AM   4028020 260059440     98.47    722640  12019516  83720748     28.94
05:40:01 AM   3929740 260157720     98.51    722720  12069520  83632964     28.91
05:50:01 AM   2719452 261368008     98.97    723460  14408924  83745112     28.95
06:00:01 AM   1530448 262557012     99.42    723644  14943264  84618304     29.25
06:10:01 AM   2925268 261162192     98.89    605748  13363596  84792452     29.31
06:20:02 AM   3235532 260851928     98.77    605916  13811664  83516740     28.87
06:30:01 AM   3265640 260821820     98.76    606072  13848028  83385196     28.83
06:40:01 AM   2102756 261984704     99.20    606232  14745508  83638764     28.92
06:50:01 AM   2386376 261701084     99.10    606644  14821232  83118484     28.74
07:00:01 AM   5343496 258743964     97.98    186908  12019804  84375032     29.17
07:10:01 AM   5073472 259013988     98.08    219044  12597104  83579876     28.90
07:20:01 AM   5380380 258707080     97.96    241300  12600412  83107160     28.73
07:30:01 AM   5063504 259023956     98.08    253984  12653840  83373804     28.82
07:40:01 AM   8241032 255846428     96.88    269960   9772232  83072188     28.72
07:50:01 AM   8549616 255537844     96.76    278472   9853288  82646916     28.57
08:00:01 AM   8185864 255901596     96.90    287296   9938816  83179808     28.76
08:10:01 AM   7797504 256289956     97.05    295856  10029904  83464160     28.86
08:20:01 AM   8813696 255273764     96.66    302620   9930672  82081220     28.38
08:30:01 AM   8574984 255512476     96.75    309156   9880124  82557600     28.54
08:40:01 AM   8010072 256077388     96.97    314804   9912220  83241764     28.78
08:50:01 AM   8791112 255296348     96.67    319568   9980532  81787424     28.28

Oracle memory usage on Linux / Unix

Hi all,

So one of the most important things that we need to do when setting up a new server or checking the capacity of the server is to see how much memory Oracle is using.

When checking the capacity there are some practical things that always help me to get a fast glimpse of the system:

  • When opening topas and hitting M you will see this below
Topas Monitor for host: SERVER1 Interval: 2 Sat Dec 8 03:39:59 2019
================================================================================
REF1 SRAD TOTALMEM INUSE FREE FILECACHE HOMETHRDS CPUS
--------------------------------------------------------------------------------
0 0 59.8G 59.6G 212.3 16.3G 528 0-15
1 1 61.4G 61.2G 188.8 15.7G 536 16-31

On the memory session you will see 3 categories, INUSE, FREE and FILECACHE. There you may see what is being using for what but there is not much granularity there.

  • When using top you have this summary below
top - 11:48:08 up 119 days, 10:18, 1 user, load average: 26.76, 26.16, 25.95
Tasks: 1936 total, 38 running, 1898 sleeping, 0 stopped, 0 zombie
Cpu(s): 79.3%us, 1.1%sy, 0.0%ni, 15.1%id, 4.3%wa, 0.0%hi, 0.1%si, 0.0%st
Mem: 263750172k total, 219075656k used, 44674516k free, 797476k buffers
Swap: 16773116k total, 505760k used, 16267356k free, 88055108k cached

Same you have a high level usage. So here comes the question:

How are you to prove that you have a memory shortage?

I often use vmstat on Linux looking on the columns si and so equals to 0 (swap in and swap out) and when the free command, the free column you will also have no or very low swap being used

/home/oracle> vmstat 1
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
15 3 505760 44896608 797480 88062288 0 0 7037 1304 0 0 29 2 61 8 0
16 1 505760 44922964 797480 88062320 0 0 432272 144314 38784 31348 41 2 52 5 0
14 2 505760 44943072 797480 88062320 0 0 468904 155424 32676 27522 34 1 60 5 0
15 2 505760 44943032 797480 88062328 0 0 431032 144275 32596 27469 34 1 60 5 0
15 2 505760 44920136 797480 88062352 0 0 396232 145052 30772 26657 32 1 62 6 0
19 1 505760 44928576 797480 88062360 0 0 429360 160158 33640 28012 36 1 58 5 0
15 3 505760 44935340 797480 88062368 0 0 477232 161849 28393 21423 41 1 53 5 0
17 1 505760 44924744 797480 88062368 0 0 515265 160212 27478 20578 40 1 54 5 0
16 1 505760 44921596 797480 88062368 0 0 495408 159304 25458 19548 37 1 58 5 0
18 1 505760 44918144 797480 88062384 0 0 552880 168895 28203 22774 38 1 56 5 0
15 2 505760 44922344 797480 88062392 0 0 546920 160463 25321 19151 37 1 58 5 0
16 4 505760 44921544 797480 88062400 0 0 571544 153810 25429 20011 36 1 58 5 0
16 1 505760 44919620 797480 88062400 0 0 577552 160004 27132 20111 40 1 54 5 0
19 2 505760 44360240 797480 88062400 0 0 584969 155553 29467 22145 41 2 52 5 0
/home/oracle> free
total used free shared buffers cached
Mem: 263750172 219060896 44689276 91608 797480 88062464
-/+ buffers/cache: 130200952 133549220
Swap: 16773116 505760 16267356

To check a process specific memory usage (RSS) I often use ps along with other commands to calculate the process memory for a specific process id as below:

/home/oracle> ps -eo rss,pid,euser,lstart,args:100 --sort %mem | grep -v grep | grep 35796 | awk '{printf $1/1024 "MB"; $1=""; print }'| sort
19.6016MB 35796 oracle Sat Sep 8 02:43:54 2018 ora_lg00_ORC1
34.957MB 32340 oracle Sat Jan 5 11:50:09 2019 oracleORC1 (LOCAL=NO)

RSS is resident memory, but when comes to shared memory like the Oracle SGA the methods above could be miss leading – not to say wrong – but as Oracle memory is shared we may see double counting on the results. I sometimes use pmap to check a process memory as well when available

/home/oracle> pmap 35796
35796: ora_lg00_ORC1
total 0K

But, still when checking a server wide scope, do you want to keep doing manual work and lots of math? I don’t think so. 🙂

That’s why when I came across SMEM made my life a lot easier. It is a python script which gives you a nice breakdown of the memory usage and without the miss leading double counting.

You can see the commands and processes and their memory:

[root@srv01 smem-1.4]# ./smem -trk | head
PID User Command Swap USS PSS RSS
4829 root /opt/stackdriver/collectd/s 444.0K 4.0G 4.0G 4.0G
5647 oracle asm_gen0_+ASM 50.1M 424.4M 425.0M 437.8M
16512 oracle rman software/product/11.2. 0 172.9M 173.7M 177.8M
85107 oracle ora_n001_db01 42.3M 147.8M 147.8M 185.8M
85103 oracle ora_n000_db01 42.4M 146.5M 146.6M 184.6M
85109 oracle ora_n002_db01 42.2M 145.6M 145.6M 183.5M
85111 oracle ora_n003_db01 42.1M 145.1M 145.2M 183.1M
7287 oracle ora_dia0_db01 1.6M 68.6M 68.8M 107.8M

As well the overall server per user:

root@srv01 smem-1.4]# ./smem -turk 
User Count Swap USS PSS RSS oracle 1358 4.8G 7.8G 8.0G 76.6G 
root 43 12.0M 4.1G 4.1G 4.2G user1 10 0 321.0M 328.0M 369.2M 
nobody 2 96.0K 2.1M 2.3M 6.0M user2 2 0 684.0K 1.7M 7.7M 
user4 2 0 632.0K 1.7M 7.9M user4 1 72.0K 536.0K 540.0K 2.1M 
ntp 1 424.0K 332.0K 368.0K 2.4M 
smmsp 1 1.3M 160.0K 298.0K 1.9M 
rpc 1 336.0K 68.0K 73.0K 1.7M 
rpcuser 1 808.0K 4.0K 16.0K 1.9M 
--------------------------------------------------- 
1422 4.8G 12.2G 12.5G 81.3G

Hope it helps, see you next time!

Amazon EC2: X11 Forwarding After Sudo SSH Session

Hello all!

So, now with more use of resources like Cloud servers, more and more silent instalations are being done, right? Myself, I do it in silent always I can.

What if I need to export X. Plus, if I need to export it from user oracle, but I can only login with ec2-user, as usual?

Here is the process for that:

1) Connect to AWS EC2 instance

[user@securehost ~]$ ssh -X ec2-user@ipaddress
Last login: Fri Dec 7 14:41:41 2018 from grepora.srv.com
__| __|_ )
 _| ( / Amazon Linux AMI
 ___|\___|___|
https://aws.amazon.com/amazon-linux-ami/2018.03-release-notes/
13 package(s) needed for security, out of 16 available
Run "sudo yum update" to apply all updates.

2) Test xclock works from ec2-user

[ec2-user@ipaddress ~]$ xclock
Warning: Missing charsets in String to FontSet conversion
^C

3) Show all magic cookie

[ec2-user@ipaddress ~]$ xauth list
ipaddress/unix:12 MIT-MAGIC-COOKIE-1 7e53e7600ff4177d7bbc66bde0a1b1ca
ipaddress/unix:11 MIT-MAGIC-COOKIE-1 e3d1a8915484c929ef3e809b047e6352
ipaddress/unix:10 MIT-MAGIC-COOKIE-1 07b3de3093cef835c19239ea952231b7

4) Show DISPLAY variable

[ec2-user@ipaddress ~]$ env|grep DISPLAY
DISPLAY=localhost:10.0

5) Create /tmp/xauth based on current DISPLAY variable

[ec2-user@ipaddress ~]$ xauth list | grep unix`echo $DISPLAY | cut -c10-12` > /tmp/xauth
[ec2-user@ipaddress ~]$ ll /tmp/xauth ; cat /tmp/xauth 
-rw-rw-r-- 1 ec2-user ec2-user 78 Dec 7 14:47 /tmp/xauth
ipaddress/unix:10 MIT-MAGIC-COOKIE-1 07b3de3093cef835c19239ea952231b7

6) Sudo to oracle

[ec2-user@ipaddress ~]$ sudo su - oracle
Last login: Fri Dec 7 14:43:12 UTC 2018 on pts/0

7) Add and Verify xauth

[oracle@ipaddress ~]$ xauth add `cat /tmp/xauth`
[oracle@ipaddress ~]$ xauth list
ipaddress/unix:10 MIT-MAGIC-COOKIE-1 07b3de3093cef835c19239ea952231b7

8) Verify and Add DISPLAY variable

[oracle@ipaddress ~]$ env|grep DISPLAY
[oracle@ipaddress ~]$ export DISPLAY=localhost:10.0

9) Test xclock works from oracle

[oracle@ipaddress ~]$ xclock
Warning: Missing charsets in String to FontSet conversion
^C
[oracle@ipaddress ~]$

Now you should be able to see the clock and so other graphical resources, like DBCA and so on.

Hope it helps!

/bin/rm: cannot execute [Argument list too long]

Hey all!

Just a quickie and useful thing today. How many times you found this?

/bin/rm: cannot execute [Argument list too long]

Ok, so, first thing: Is it related to Oracle logs? If so, you may want to ADCRI. Check this post for more info: ADRCI Retention Policy and Ad-Hoc Purge Script for all Bases.

If not, you may solve this using find with rm. Ok, but want to keep the most recent files?

Some examples for you, removing audit files:

# Remove older then 1 day:

find /oracle/greporadb/admin/greporadb/adump -name "*.aud" -mtime +1 -exec rm {} \;

# Remove older then 1 hour:

find /oracle/greporadb/admin/greporadb/adump -name "*.aud" -cmin +60 -exec rm {} \;

More“/bin/rm: cannot execute [Argument list too long]”

IPv6 Formatting for JDBC and SQLPlus

Hey all!
Seems new right? But it’s available since 11gR2.
Not needed to explain what is IPV6, right? Any questions, go here.

In summary the only thing you need is to enclose the IPv6 address in square brackets. Like this:

For Easy Connect on IPV4:

SQL> connect user/pass@172.23.10.40:1521/GREPORADB
Connected.

 

For Easy Connect on IPV6:

SQL> connect user/pass@[1:95e05a:g0d:da7a:2007]:1521/GREPORADB
Connected.

For JDBC (thin) IPV4:

url="jdbc:oracle:thin:@(DESCRIPTION=
(LOAD_BALANCE=on) (ADDRESS_LIST=
(ADDRESS=(PROTOCOL=TCP)(HOST=172.23.10.40) (PORT=1521))
(ADDRESS=(PROTOCOL=TCP)(HOST=172.23.10.41)(PORT=1521)))
(CONNECT_DATA=(SERVICE_NAME=GREPORADB)))"

For JDBC (OCI) IPV4:

url="jdbc:oracle:oci:@(DESCRIPTION=(ADDRESS=
(PROTOCOL=TCP)(HOST=172.23.10.40)(PORT=1521))
(CONNECT_DATA=(SERVICE_NAME=GREPORADB)))"

For JDBC (thin) IPV6:

url="jdbc:oracle:thin:@(DESCRIPTION=
(LOAD_BALANCE=on) (ADDRESS_LIST=
(ADDRESS=(PROTOCOL=TCP)(HOST=[1:95e05a:g0d:da7a:2007]) (PORT=1521))
(ADDRESS=(PROTOCOL=TCP)(HOST=[1:95e05a:g0d:da7a:2006])(PORT=1521)))
(CONNECT_DATA=(SERVICE_NAME=GREPORADB)))"

For JDBC (OCI) IPV6:

url="jdbc:oracle:oci:@(DESCRIPTION=(ADDRESS=
(PROTOCOL=TCP)(HOST=[1:95e05a:g0d:da7a:2007])(PORT=1521))
(CONNECT_DATA=(SERVICE_NAME=GREPORADB)))"

As you can imagine, the same applies to your TNSNAMES entries.

Also, according to this, it can be used even for your LISTENER:

LISTENER =
 (DESCRIPTION_LIST =
  (DESCRIPTION =
   (ADDRESS =
    (PROTOCOL = TCP)
    (HOST = [1:95e05a:g0d:da7a:2007])(PORT =1521))
  )
 )

Cheers!

Change display settings on linux with Disper

From time to time, I change the Linux distro on my laptop or just do a fresh install on it. And once in a while, have random problems with external displays. It can be something really “simple” like don’t detecting the external monitor or something crazy like the image below.

screenshot of the bug

As you can see at the image, the mint detected the display but mirrored it in a crazy way that works but doesn’t at the same time. If you try anything and doesn’t get working, or just wanna skip the whole job of configuring complexes text files, give a try to Disper. Download the latest version. Extract it on any folder, and make install it (on the extracted folder).

make install

After that, you can start using it… There are a few options that will serve you well.

disper -e #extend your display
disper -c #clone your display
displer -s #only your external display