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10 Newer Entries Showing entries 61 to 70 of 1147 10 Older Entries

Displaying posts with tag: Linux (reset)

OL 4 MySQL: Extending my VM’s root f/s online
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Ok, so after all the things that have been announced @MySQLConnect, I’ve got to play around with them. First stop: space (no.. not ‘the final frontier’).

I need more space on my f/s to get installing. I was a bit of a scrooge when I created my Oracle Linux virtual machine, so now I’m paying the price.

Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_ol63uek01-LogVol01
                      7.1G  5.7G  1.1G  85% /

As I’m using Virtual Box, I’ve added a new SATA Controller vmdk of 10G, SATA Port 1 and then start it up.

fdisk -l

Will be able to identify the new & unused partition:

[root@ol63uek01 ~]# fdisk -l
Disk /dev/sda: 8589 MB, 8589934592 bytes
 255 heads, 63 sectors/track, 1044 cylinders
 Units = cylinders of
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Setting up WordPress on Debian/Ubuntu running Tengine web server
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I will change my host provider within a month. I’ve been using Midphase for several years and have decided to use Linode as my next virtual private service provider. I will move this site there in the next few weeks. This will be my first time moving a domain and I hope the transfer will be smooth without too much down time. After all, I know my readers worldwide are hanging on to every word I type and deserve a site that runs 24 by 7

Since I will have total control of this host, I decided to use Tengine, a great fork of the Nginx web/proxy server. Here is my note on how to compile and config Tengine on Debian/Ubuntu, and then setup WordPress. During my study and testing, the following sites are pretty

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#DBHangOps 9/17/13 — Data Warehousing, MySQL-isms, and MySQLConnect!
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And that’s a wrap! Check out the recording:

Hello!

Coming up this Wednesday, September 18th, 2013 at 12:00pm pacific (19:00 GMT) come and join #DBHangOps to discuss:

  • Data warehousing in MySQL
    • Shipping large tables from production to your Data warehouse
    • Do you use Federated engine?
    • What other solutions do you use?
  • Answer some questions about MySQL-isms (requested by Tim Callaghan)
    • Why does MySQL have FRM files instead of storing them in a data dictionary table?
    • Why doesn’t InnoDB support other page sizes?
    • Why do we store data in a master.info file?
  • What are you excited to see at MySQLConnect?

As always, take a


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Limit The Size of Your Core Files on Linux
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So we all know that when troubleshooting MySQL crashes or any other processes in that regard, we simply enable core files to be dumped when the appropriate signal it triggered. To get the best results, we’d set the core file size limit everywhere to unlimited and be done with it, but what if you want to limit that to a certain size? I stumble to a small confusion lately when doing this for MySQL, so let me share quickly.

First, for MySQL, mysqld_safe would use ulimit to set the core-file-size value you pass to it. Now remember according to the manual, this value should be in blocks (some documentation says its in chunks of 1024 bytes). However, according to my experience on CentOS 6, this is the physical block size of the device where your core_pattern is pointed to.

[root@centos6 ~]# ulimit -a
...
core file size          (blocks, -c) 0
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#DBHangOps 9/4/13 — Data dictionary corruption, MySQL Utilities, Benchmarking, and MySQLConnect!
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Check out the video!
Hey there everybody!

Coming up this Wednesday, September 4th, 2013 at 12:00pm pacific (19:00 GMT) take part in #DBHangOps to discuss:


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Trick: recovering from "no space left on device" issues with MySQL
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Just read Ronald Bradford's post on an unnecessary 3am (emergency) call. I sympathize! Running out of disk space makes for some weird MySQL behaviour, and in fact whenever I encounter weird behaviour I verify disk space.

But here's a trick I've been using for years to avoid such cases and to be able to recover quickly. It helped me on such events as running out of disk space during ALTER TABLEs or avoiding purging of binary logs when slave is known to be under maintenance.

Ronald suggested it -- just put a dummy file in your @@datadir! I like putting a 1GB dummy file: I typically copy+paste a 1GB binary log file and call it "placeholder.tmp". Then I forget all about it. My disk space

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#DBHangOps 8/21/13 — Fractal indexes in TokuDB and Schema tracking
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Hey all!

Coming up this Wednesday, August 21st, 2013 at 12:00pm pacific (19:00 GMT) join in to talk about:

  • Gerry from Tokutek to talk about B-Tree indexes in InnoDB and fractal indexes TokuDB!
  • Schema Versioning
    • How do you manage schema versions in your development pipeline?
    • How are your schema changes deployed? Is it automated?
    • Some automated schema management tools:
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Tool of the day: q
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If you work with command line and know your SQL, q is a great tool to use:

q allows you to query your text files or standard input with SQL. You can:

SELECT c1, COUNT(*) FROM /home/shlomi/tmp/my_file.csv GROUP BY c1

And you can:

SELECT all.c2 FROM /tmp/all_engines.txt AS all LEFT JOIN /tmp/innodb_engines.txt AS inno USING (c1, c2) WHERE inno.c3 IS NULL

And you can also combine with your favourite shell commands and tools:

grep "my_term" /tmp/my_file.txt | q "SELECT c4 FROM - JOIN /home/shlomi/static.txt USING (c1)" | xargs touch

Some of q's functionality (and indeed, SQL functionality) can be found in command line tools. You can use grep for pseudo

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Public DNS resolve for VM instances hosted at OpenStack nova compute grizzly edition
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Issue – the OpenStack instances hostnames are not resolved at the moment by their floating IPs.

Fast solution – use PowerDNS
Short story:
1. Boot an instance , assign it a floating IP, open tcp ports 22 8001 and udp port 53.
2. Install PowerDNS, the particular yum package is named pdns.
3. install the mysql backend for PowerDNS, its available as yum package as well.
4. Install MariaDB , set the proper configuration, the initialize it at the default location.
5. Set the pdns user, create the pdns database and create the tables needed.
6. Configure the pdns service to use the gmysql backend.
7. Create and user at the OpenStack MySQL able to connect from the floating IP subnet.
8. Grant that user select permissions on all nova.* tables.
9. At the PowerDNS









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#DBHangOps 7/24/13 — Innobackupex, schema migrations, and more!
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And all set. Check out the recording:

Hello everybody!

Coming up this Wednesday, July 23rd, 2013 at 12:00pm pacific (19:00 GMT) join in to hear:

  • Brandon Johnson from Mozilla talk about an issue he recently worked through with XtraBackup and the process he took to identify and resolve the issues.

And also take part in discussion around:

  • How do you apply production schema changes?
    • Do you use pt-online-schema-change?
      • Issues to watch out for
    • Just run the alter!
    • Pull from a pool and apply

Make sure to follow the #DBHangops twitter search, the DBHangops Twitter Feed, or this blog post to get a link for the google hangout on Wednesday!

Excited to see all of you joining in on the conversation!

10 Newer Entries Showing entries 61 to 70 of 1147 10 Older Entries

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