My latest feature article for TechNet Magazine has just been published in the April edition. It focuses on planning an HA/DR strategy within the confines of a larger corporate IT strategy, from multiple perspectives but really focusing on the IT manager role and how to interact both up (to business managers) and down (to DBAs). [...]
Paul S. Randal
In Recovery...
TechNet Magazine article: data protection and the corporate jigsaw puzzle
Posted on: April 6, 2011 11:27 am
Importance of network latency when using database mirroring
Posted on: February 8, 2011 10:02 am
Last week I kicked off a survey about network latencies and database mirroring. See here for the original post. Here are the results of the survey: I was really interested to see whether the proportion of people doing asynchronous mirroring became higher as the network latency increased. Although this isn't a statistically valid sampe [...]
Importance of monitoring a database mirroring session
Posted on: January 31, 2011 12:29 pm
Last week I kicked off a survey about how you monitor your database mirroring sessions. See here for the original post. Here are the results of the survey: The "Other" values were: 6 people monitor mirroring session state changes One uses a 3rd-party product to do monitoring One monitors response time for the application [...]
Survey: database mirroring latency between servers
Posted on: January 30, 2011 11:10 am
In my survey for this week, I'd like to know what you what the network latency is between your mirroring principal and mirror servers, and what kind of mirroring you're using. I'll report on the results during the second week of February. Thanks!
Survey: monitoring database mirroring
Posted on: January 24, 2011 11:12 am
In my survey for this week, I'd like to know what you monitor if you're using database mirroring. [Edit: The survey has closed now. See here for the results.] I'll report on the results during the first week of February. Thanks!
In defense of transactional replication as an HA technology
Posted on: November 3, 2010 10:28 am
Yesterday on Twitter a few people expressed disgust at a conference slide listing transactional replication as a high-availability (HA) technology. I took exception to that and argued. I think the discussion merits a blog post so here it is. This point of view is controversial and I'm expecting some dissenting comments – bring them on! I teach [...]
Whitepaper on high-availability architectures published
Posted on: June 4, 2010 11:00 am
The 20-page whitepaper I wrote this Spring for the SQL team has just been published. This whitepaper is titled Proven SQL Server Architectures for High Availability and Disaster Recovery and ties in with the longer whitepaper I wrote last year on High Availability with SQL Server 2008 (see here). This new whitepaper describes the five [...]
Important things for DBAs to consider
Posted on: April 12, 2010 4:31 pm
(Look in the Misconceptions blog category for the rest of the month’s posts and check out the 60-page PDF with all the myths and misconceptions blog posts collected together when you join our Insider list, plus my online Myths and Misconceptions training course on Pluralsight.) Over the last month or so I've found myself handing [...]
A SQL Server DBA myth a day: (7/30) multiple mirrors and log shipping load delays
Posted on: April 7, 2010 6:54 am
(Look in the Misconceptions blog category for the rest of the month’s posts and check out the 60-page PDF with all the myths and misconceptions blog posts collected together when you join our Insider list, plus my online Myths and Misconceptions training course on Pluralsight.) A short one today as I'm teaching a class on [...]
A SQL Server DBA myth a day: (1/30) in-flight transactions continue after a failover
Posted on: April 1, 2010 10:32 am
(Look in the Misconceptions blog category for the rest of the month’s posts and check out the 60-page PDF with all the myths and misconceptions blog posts collected together when you join our Insider list, plus my online Myths and Misconceptions training course on Pluralsight.) Fellow MVP Glenn Berry (Twitter|blog) has just started a blog [...]
Things to consider when setting up database mirroring
Posted on: October 14, 2009 8:27 pm
Over the last week or so I've been helping the Product Support folks at Microsoft write a new KB article which discusses some of the things you should take into consideration when setting up database mirroring. It discusses memory, CPU, I/O bandwidth, network bandwidth, and transaction volume. One of the most interesting things it discusses [...]
SQL Server 2008 High Availability whitepaper published on MSDN
Posted on: September 28, 2009 12:42 pm
The 35-page whitepaper on high availability I wrote for the SQL team over the summer has been published on MSDN. It's a 2-300 level whitepaper that describes the various high-availability technologies in SQL Server 2008 and how they can be used to mitigate disasters. It's chock-full of links to other whitepapers, technical articles and Books [...]
Adding geo-redundancy to failover clustering
Posted on: August 26, 2009 12:07 pm
A few weeks ago I kicked off a survey on how you add geo-redundancy to a failover cluster (see here for the survey). The results as of 8/26/09 are as follows: So why is this interesting? Well, many people will suggest failover clustering as the best way to provide high-availability for a database (or [...]
Survey: How do you provide geo-redundancy with clustering?
Posted on: August 3, 2009 2:59 pm
I'm moving away from strictly weekly surveys as they're a little demanding, especially when we're on the road. In this survey I'd like to know which technology you use to provide geo-redundancy to databases that are protected locally using a failover cluster. I'll report on the answers sometime around the middle of August. *Please* no comments [...]
Importance of defining and measuring SLAs
Posted on: May 30, 2009 4:00 pm
In last week's survey I asked you two things, as a precursor to a whitepaper I'm writing for Microsoft The first question was what is your maximum allowable downtime SLA (either for 24×7 operation or not). See here for the survey. Here are the results as of 5/30/09. The Other values were all about not having [...]
Weekly survey: maximum allowable downtime – target and actual
Posted on: May 25, 2009 1:58 pm
This week's survey is inspired by this morning's Kimberly+Paul hot-tub conversation around data-dependent routing vs. network load balancing, which then turned to SLAs. Yes, we lead an exciting life . This survey is a *four*-parter. Part 1 is for each of your databases, which survey option is closest to your target maximum allowable downtime SLA (Service-Level [...]
Weekly survey: have you ever tested your disaster recovery plan?
Posted on: May 17, 2009 5:38 pm
This week's survey is inspired from many stories I saw on the forums and Twitter this week – mostly bad, one good (someone I'm following is spending the weekend testing their disaster recovery plan – cool!). I'd like to know whether you're ever tested your disaster recovery plan, and if so, what happened? I'll report [...]
Weekly survey: what’s your largest database, and how many do you manage?
Posted on: May 2, 2009 7:58 am
Jason Massie posted an interesting statistic yesterday – Facebook has 1.5 petabytes of image storage, and it grows by 25TB daily – I wonder how they store and manage it? In this week's survey, I'm interested in two things: what's the largest single SQL Server database in your company and how many SQL Server databases [...]
Physical database layout vs. database size
Posted on: April 27, 2009 12:21 am
A couple of weeks ago I kicked off the latest survey, on what the physical layout of your databases are and why you have them that way (see here for the survey). I let the survey run for a while to get a good sampling, and I wasn't disappointed, with over 1000 responses! Here are [...]
Why could restoring a log-shipping log backup be slow?
Posted on: April 21, 2009 5:48 pm
A short post to start the day (in India) and then at lunchtime I'll do how it works: FILESTREAM garbage collection. This is a question that came up recently on an MVP discussion list: why does a 200MB log backup take 40 minutes to restore on my log-shipping secondary? First answer I thought of was [...]
Weekly survey: does size really matter – or is it what you do with it?
Posted on: April 10, 2009 3:05 pm
This week's survey is a little more complicated. I'm interested in the physical layout of your databases. I've got four surveys, for a variety of database sizes. Please vote multiple times in each survey, as you see fit – and by all means forward this link to your friends/clients/etc or re-blog/tweet it. I'm going to report [...]
Importance of validating backups
Posted on: March 13, 2009 5:17 pm
Last week I kicked off the first weekly survey – on whether you validate your backups or not (see here for the survey). The results are very interesting (as of 3/13/09): As you can see, almost 25% of respondents never validate their backups! And a further 25% only validate them occasionally, with 30% doing some [...]
Rolling upgrade using database mirroring (and a bug in 2008 RTM)
Posted on: February 24, 2009 11:00 am
While trawling through the latest 2008 Books Online this morning to answer a question, I noticed a new section that I hadn't seen before, which explains in detail how to perform a rolling upgrade with database mirroring. The link to the MSDN page is http://msdn.microsoft.com/en-us/library/bb677181.aspx and below I've linked to the flowchart from that page. Books [...]
TechNet Magazine: February 2009 SQL Q&A column
Posted on: January 16, 2009 10:15 am
OK – last content post today. I forgot that the February TechNet Magazine also has the latest edition of my regular SQL Q&A column. This month's column covers: Should backup compression be enabled at the instance level? Client redirection during database mirroring failovers Partition-level lock escalation in SQL Server 2008 Is it ever safe to [...]
TechNet Magazine: December 2008 SQL Q&A column
Posted on: November 12, 2008 11:51 am
It's really scary how quickly time flies – seems like it was just last week when I last blogged about TechNet Magazine (actually it was a month ago when I blogged about my 2008 Change Tracking article - see here). Anyway, a new issue of TechNet Magazine has just come out and this one has the [...]
Planning a backup strategy – where to start?
Posted on: October 26, 2008 11:13 am
It's been almost exactly a week since the last post – an unusually long time for me. Kimberly and I were teaching the first week of the inaugural Microsoft Certifed Masters SQL course last week in Redmond (a little intense at 8 hours of *teaching* per 10-hour day – so no energy for blogging afterwards). [...]
Reminder of why hardware redundancy is a good thing
Posted on: October 19, 2008 2:59 pm
One of our customers (and friends!) sent us this last week – a stark reminder why hardware redundancy is a good idea! The controller card in one of his servers literally blew up at 7.15am Tuesday morning. Although they didn't have redundant hardware, they were back online by 9am – pretty good going. Funnily [...]
SQL Server2008: New whitepaper on combining transactional replication and database mirroring
Posted on: September 2, 2008 8:05 pm
I just heard today that the first whitepaper I’ve written for Microsoft has been published! The abstract is: SQL Server Replication: Providing High-Availability using Database Mirroring This white paper describes how to use database mirroring to increase the availability of the replication stream in a transactional environment. It covers setting up replication in a mirrored [...]
How to tell if you have instant initialization enabled?
Posted on: August 11, 2008 7:10 pm
As you may already know, instant initialization is a way to prevent data (not log) file create and grow operations having to zero-initialize the new space before allowing it to be used. This can vastly speed up these operations as zero-initialization can take a *long* time for large files. This is especially useful in disaster [...]
TechEd Online Panel Video: Building a Solid High-Availability Strategy
Posted on: July 21, 2008 6:00 pm
While we were at TechEd in June, Kimberly and I participated in an hour-long discussion panel (Leveraging SQL Server Technologies to Build a Solid High-Availability Strategy) that was video-taped by the TechEd Online folks. It’s now been edited and is available for download/viewing. We cover everything from requirements analysis to technology details in SQL Server [...]
HA: Where do you start when choosing a high-availability solution?
Posted on: March 13, 2008 9:14 pm
It seems that today is going to be one of those days where I get lost in forums and blogging – I can live with that :-) One of the questions that came up on a forum today was about choosing an HA solution – based solely on the hardware that was running the database! [...]
