In my previous post I covered the shard-disk paradigm's pros
and cons, but the conclusion that is that it cannot really
qualify as a scale-out solution, when it comes to massive OLTP,
big-data, big-sessions-count and mixture of reads and
writes.
Read/Write splitting is achieved when numerous
replicated database servers are used for reads. This way the
system can scale to cope with increase in concurrent load. This
solution qualifies as a scale-out solution as it
allow expansion beyond the boundaries of one DB, DB
machines are shared-nothing, can be added as a slave to the
replication "group" when required.
And, as a fact, read/write …
Jun
20
2012
Jun
18
2012
As I reported via Twitter late last week, we encountered an issue that got some of our mail delivery delayed by about a day and a half. I’ll explain more about what happened as I believe in openness on these matters, and also the experience has educational content for others.
Our mail server doesn’t have direct external interaction, it’s shielded by two relays that handle both the inbound MX and the outbound queue. This setup works remarkably well in terms of exposure to spam and other malicious activity. As previously discussed, it appears that it’s more difficult to make mail server infra more resilient without expending lots more time/effort and infrastructure expenditure. Just because of the way the common tools for mail delivery and imap are built, having two or more of each in a semi-active setup gets quite complex. Complexity is in itself a risk so it has to be considered in relation to the costs and risks of the …
[Read more]
Jun
13
2012
Over the past few days extensive conversations around a new security vulnerability in MariaDB and MySQL have taken place.
It all started as a chain reaction when Monty Program publicly disclosed information about the flaw they had found and about how to make sure your MariaDB and MySQL installations can be fixed. The initial information got assigned the security vulnerabitlity identifier CVE-2012-2122 and the contents can be seen e.g. here http://seclists.org/oss-sec/2012/q2/493 .
The bug was found two months ago on April 4th.
Jun
13
2012
Cloud-powered BLOB type provides ACID guarantees and fast direct access to blobs via Web URLs.
Storing unstructured data
Typically unstructured data (such as pictures, media files, documents)
a) Is either stored on the file system, unlike the related with it relational data which is stored in the database. This is well known, “convenient” practice that allows fast access to files but offers no transactional story and no unified data management (for db and filesystem)
b) Or is stored in BLOBs. This ensures transactional consistency and reduces management complexities, but is really bad for performance and scalability.
We took advantage of the cloud, and came up with an upgrade to
the BLOB – a solution that combines the benefits of the
two.
Weblob data type
Weblob is a new data type that is supported by the Cloud Storage Engine for MySQL ( …
[Read more]
Jun
12
2012
Retrouvez SkySQL et ses partenaires sur le stand C21 du Salon Solutions Linux 2012 au CNIT à Paris du 19 au 21 juin
Cette année, le Salon Solutions Linux à Paris coincide avec la Fête de la Musique. C’est donc avec enthousiasme que nous nous préparons pour cet évènement annuel incontournable dédié aux logiciels libres et à l’Open Source.
Jun
11
2012
I found time to continue my previous work on group commit for the binary log in MariaDB.
In current code, a (group) commit to InnoDB does not less than
three fsync() calls:
- Once during InnoDB prepare, to make sure we can recover the transaction in InnoDB if we crash after writing it to the binlog.
- Once after binlog write, to make sure we have the transaction in the binlog before we irrevocably commit it in InnoDB.
- Once during InnoDB commit, to make sure we no longer need to scan …
Jun
07
2012
Yesterday I was asked by a customer for the reason why he had
failed to achieve scale with a state-of-the-art "shared-storage"
cluster. "It's a scale-out to 4 servers, but with a shared disk.
And I got, after tons of work and efforts, 130% throughput,
not even close to the expected 400%" he said.
Well, scale-out cannot be achieved with a shared storage and the
word "shared" is the key. Scale-out is done with
absolutely nothing shared or a "shared-nothing"
architecture. This what makes it linear and
unlimited. Any shared resource, creates a tremendous burden
on each and every database server in the cluster.
In a previous post, I identified database engine
activities such as buffer management, locking, thread
locks/semaphores, and recovery tasks - as the main bottleneck in
the OLTP …
May
30
2012
Today, I think we witnessed a small sign for a big
revolution...
http://www.pcworld.com/businesscenter/article/256383/dell_reaches_for_the_cloud_with_new_prototype_arm_server.html
"Dell announced a prototype low-power server with ARM processors,
following a growing demand by Web companies for custom-built
servers that can scale performance while reducing financial
overhead on data centers"In short, ARM (see Wikipedia definition
here) is an architecture standard for processors.
ARM processors are slower compared to good old x86 processors
from Intel and AMD, but have power-efficiency, density and price
attributes that intrigue customers, especially in our days of
green data centers where carbon emissions is …
May
28
2012
1. Percona Toolkit
Percona Toolkit (aka Maatkit and Aspersa) is must have collection
of advanced command-line tools which helps in performing tasks
that are too difficult or complex to perform manually.
2. Mydumper
Mydumper is a high-performance multi-threaded backup/restore tool
for MySQL. It’s up to 10x faster compared to mysqldump, can take
consistent snapshots and provides File compression on-the-fly.
Though it’s still under active development but is well
tested/used in production on some large installations.
3. MySQL Master HA
This tool helps to maintain your Master-Slave replication setup.
A primary objective is automating master fail-over and slave …
May
26
2012
In Ausgabe 3/2012 der Fachzeitschrift JavaSPEKTRUM wurde kürzlich ein Artikel mit dem Titel "SOA-basierte NoSQL-Lösung im Mobile-Umfeld" veröffentlicht, dessen Co-Autor ich bin. Er beschreibt, wie eine mobile Java-Applikation mittels kreativer Ansätze und einem Mix aus moderner und altbewährter Technik zum Erfolg gebracht wurde.
Der Volltext kann entweder im Browser auf der codecentric Homepage unter der Rubrik Kompetenzen/Publikationen gelesen werden, steht aber auch als PDF zum Download bereit.