Voice of the DBA

Tag: administration

  • Creating Placeholder Files

    I recently wrote about placeholders for disk space. While you can use any file, like large images, video, etc., I’ve found a really simple, easy way to build these files on Windows.

    Contig.exe

    There’s a sysinternals utility called Contig. You can download it from Microsoft and then unzip it on your system. It’s a command line utility, so you can use the /? to get the parameters from it, but here’s what you need to do: use the -n parameter, with a filename and a size.

    That simple. Here’s a sample call:

    placeholders1

    And in text:

    contig -n Hold1.place 1073741824

    That creates a 1GB file (roughly) on my system. I can then copy this file as many times as I want to save space.

    I use folder in the root called placeholder. I put one file in there and then copy it a few times to reserve space.

    Why that size? 1024 * 1024 * 1024.

  • Consolidating Again and Again and Again

    This editorial was originally published on November 12, 2009. It is being re-run as Steve is on holiday. 

    In reading about virtualization, one of the main things that drives its acceptance is cost. It’s the reduction in actual physical resources needed to run multiple servers that makes it popular with many IT departments. It doesn’t help with administrative costs, at least not the costs of the system administrators because you still have the same number of servers to manage. There are just less physical servers to buy, less power needed, less cooling, and probably other savings if you virtualize.

    Virtualization is really a one-time cost savings. Once you’ve virtualized a server, you can’t do I again, so there are no repeat savings from this event. Is consolidation the same? After all, the main driving force for that process is also cost, and once you’ve consolidated a server you can’t do it again.

    Or can you?

    There’s a great white paper by Allan Hirt that talks about the process of consolidation, and I’d urge you to read it before beginning a consolidation project. However I don’t know that consolidation is, or should be, a large, one-time project.

    If I consolidate 3 or 5 SQL Server instances onto one machine, I have a choice of how I can do this. It can be by moving databases to a new instance, having multiple instances, or even using virtual machines. But is that the end? It’s not because I can add more databases later, or I could even move a database that is receiving a heavy load back to its own server and find other instances to consolidate onto this one.

    Consolidation, unlike  virtualization ought to be something you periodically examine in your environment. On a regular basis review your baseline for all instances and see if it makes sense to perform some consolidation. Server sprawl can creep up on you, but with a little management and the multi-instance nature of SQL Server, you can keep it under control.

    And if you don’t have a baseline to examine, consider setting one up.

    Steve Jones

  • Placeholders for Emergencies

    A long time ago I worked in a large corporation where we managed lots of servers, each of which performed a variety of different functions. Some were Exchange, some SQL, some file servers, etc. and they would come and go at a frightening pace.

    We had monitoring in place, but we’d also have plenty of situations where a runaway process would use up a lot of disk space at a rate that exceeded the ability of the monitoring software to alert us before the user encountered a problem. To help us more effectively monitor things, we started adding placeholders do our server build process.

    Placeholders

    What’s a placeholder? It’s a large file that just takes up space on a disk. For example, I’ve created a few on my system:

    placeholders2

    These can be text files, movies, images, whatever you want. The idea is that you just save a particular amount of space. In this case, I have 3 1GB files that are taking up space.

    That’s it.

    If I run out of disk space, I just delete one of these, and voila, instant 1GB space available.

    These have become really, really handy for me. I actually have a few on my laptop. When I run low on space, which will often happen at THE WORST possible time, like the morning of a talk, I can remove a file and free up space.

    Of course, I’ve just deferred the issue, but at least then I can work at that moment and then clean up old files as I have a moment.

    Placeholders are a great way to save yourself in emergencies.

  • How Often Does Production Drift?

    One of the new products that Red Gate Software is working on is SQL Lighthouse, which is designed to track and alert you on “database drift“, which are the changes in your schema. I hadn’t really heard the concept in the past, though I’ve found there are a few people using the term to describe the changes being made to production that aren’t inline with the development project that created (and updates) the database.

    Vendors that sell products backed by a SQL Server database, like Microsoft Dynamics, often consider database drift to be a violation of their EULA. When a customer changes the database, even by just adding indexes, it causes them support costs, though arguably those costs are lower than if no indexes were ever added by enterprising DBAs.

    However this also happens in databases built by companies. It seems there’s no shortage of “quick fixes” in production, in addition to the “improvements” that DBAs and others seem to make to their live databases in order to solve some short term issue. I know there’s a need for this, and even seen recommendations to ensure production differs from development schemas. However I haven’t had many issues with this in the past and I’ve tried to prevent any drift.

    Maybe because I’m a controlling DBA, or maybe because I’ve been lucky. In either case, while I’ve had to implement hot fixes and changes in production, it’s been rare. Most of the time I’ve been able to backfill these changes in development (and test) environments, or delay the fix until it could be tested.

    However I’m sure there’s a need for a way to manage drift, and detect it as the number of databases you manage grows, so I’m excited by SQL Lighthouse and hope it helps DBAs avoid those late night phone calls by being aware of what’s changing in their systems.

    Steve Jones

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