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Displaying posts with tag: Linux (reset)
osquery is neat

Facebook recently made opensource, osquery. It gives you operating system data via SQL queries! Its very neat, and you can test this even on MacOSX (it works on that platform & Linux). It is by far the project with the most advanced functionality, linked here in this post.

I noticed that rather quickly, there was a PostgreSQL project, called pgosquery, based on Foreign Data Wrappers with a similar idea. (apparently it was written in less than 15 minutes; so a much lower learning curve than the regular MySQL storage engine interface)

I immediately thought about an older MySQL project, by Chip Turner (then at Google, now at Facebook), called …

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What is Iptables, what it’s for, and how to use?

After a long time, I finally had some time to write again, and this time I intend to keep a periodicity. The reason for my absence? Well now I have Dom Without further ADO, let’s get to the point, what… Continue Reading →

Continue reading What is Iptables, what it’s for, and how to use?

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The Perfect Server - Ubuntu 14.10 with Apache, PHP, MySQL, PureFTPD, BIND, Postfix, Dovecot and ISPConfig

The Perfect Server - Ubuntu 14.10 with Apache, PHP, MySQL, PureFTPD, BIND, Postfix, Dovecot and ISPConfig

This tutorial shows how to install an Ubuntu 14.10 (Utopic  Unicorn) server (with Apache2, BIND, Dovecot) for the installation of ISPConfig 3, and how to install ISPConfig 3. ISPConfig 3 is a webhosting control panel that allows you to configure the following services through a web browser: Apache or nginx web server, Postfix mail server, Courier or Dovecot IMAP/POP3 server, MySQL, BIND or MyDNS nameserver, PureFTPd, SpamAssassin, ClamAV, and many more. This setup covers the installation of Apache (instead of nginx), BIND (instead of MyDNS), and Dovecot (instead of Courier).

The Perfect Server – CentOS 7 (Apache2, Dovecot, ISPConfig 3)

The Perfect Server – CentOS 7 (Apache2, Dovecot, ISPConfig 3)

This tutorial shows how to prepare a CentOS 7 x86_64 server for the installation of ISPConfig 3 and how to install ISPConfig 3. ISPConfig 3 is a webhosting control panel that allows you to configure the following services through a web browser: Apache web server, Postfix mail server, MySQL, BIND nameserver, PureFTPd, SpamAssassin, ClamAV, Mailman, and many more.

XFS and EXT4 Testing Redux

In my concluded testing post, I declared EXT4 my winner vs XFS for my scenario. My coworker, @keyurdg, was unwilling to let XFS lose out and made a few observations:

  • XFS wasn’t *really* being formatted optimally for the RAID stripe size
  • XFS wasn’t being mounted with the inode64 option which means that all of the inodes are kept in the first 2TB. (Side note: inode64 option is default in newer kernels but not on CentOS 6’s 2.6.32)
  • Single threaded testing isn’t entirely accurate because …
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More EXT4 vs XFS IO Testing

Following my previous post, I got some excellent feedback in the forms of comments, tweets and other chat. In no particular order:

  • Commenter Tibi noted that ensuring I’m mounting with noatime, nodiratime and nobarrier should all improve performance.
  • Commenter benbradley pointed out a missing flag on some of my sysbench tests which will necessitate re-testing.
  • Former co-worker @preston4tw suggests looking at different IO schedulers. For all tests past, I used deadline which seems to be best, but re-testing with noop could be useful.
  • Fellow DBA @kormoc encouraged me to try many smaller partitions to limit the number of concurrent fsyncs.

There seem to be …

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IO, IO, It’s Off to Testing We Go

In my last post, I learned in disappointing fashion that sometimes you need to start small and work your way up, rather than trying to put together a finished product. This go-round, I’ll talk about my investigation into disk IO.

In an effort to better understand the hardware I have and it’s capacities, I started off by just trying to get some basic info about the RAID controller and the disks. This hardware in particular is a Supermicro, with a yet unknown RAID controller and 16 4TB disks arranged in RAID 6. Finding out more disk and controller information was the first step. “hdparm -i” wasn’t able to give me much, nor was “cat /sys/class/block/sdb/device/{model,vendor}”. “dmesg” …

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Even If You Fail, You Can Still Learn

As many learning experiences do, this one also starts out “So I was working on a project at work and…”.  In this case, the end result is to try to run as many concurrent copies of MySQL on a single server as possible, maintaining real time replication each running differing data sets. To help with this, I sent out to do this on a server with 36 7200rpm 4GB SATA disks, giving me roughly 120TB of available space to work with.

This isn’t an abnormal type of machine for us. Sometimes you simply need a ton of disk space. There is a quirk with this particular machine that I’ve been told: the RAID controller has some issues with addressing very large virtual disks and I should create 2 60TB volumes and stitch them together with LVM. Easy enough: pvcreate both volumes, create a volume group and a logical volume out of it and viola: …

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How to start Percona Xtradb Cluster on CentOS 7

Normally, when we want to start PXC (Percona XtraDB Cluster) on RHEL/CentOS 6 or older then that, we can simply start with init.d script or service command. i.e

shell> /etc/init.d/mysql start 
OR 
shell> /etc/init.d/mysql bootstrap-pxc
shell> service mysql start.

But, the way is changed from CentOS 7. Because systemd integration with RHEL/CentOS 7 is now available for Percona XtraDB Cluster (#1342223).

So now, we have to start mysql with systemctl command i.e

shell> systemctl start mysql

For boostrap,

shell> systemctl start mysql@bootstrap.service

I would also suggest to read one very informative post by Przemek for recovering PXC cluster. …

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Is automation killing old-school operations?

Join 27,000 others and follow Sean Hull on twitter @hullsean. I was shocked to find this article on ReadWrite: The Truth About DevOps: IT Isn’t Dead; It’s not even Dying. Wait a second, do people really think this? Truth is I have heard whispers of this before. I was at a meetup recently where the […]

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