The maths most SAN engineers do not understand in context of Database Servers 6

I suppose I write this post to mock some of the things I keep seeing in the industry today. Directly Attached Storage (DAS) has moved on dramatically in the past 5 years, a single SSD has the capability of up to 525MBytes/sec throughput (SATA/SAS 6Gbits/sec), 700MBytes/sec (M.2) and then there is PCIe connected flash operating […]

Maximum IOPS for a 10K or 15K SAS Hard Disk Drive is not 170! 5

At times, mmm quite often now actually (perhaps it’s because I’m getting older and more grumpy) the industry I’m part of really makes me embarrassed, all too often folk just quote things they’ve seen on Wikipedia or via word of mouth without even a basic knowledge of the “fact” they are quoting – a “fact” […]

Hard Disk Short-stroking (Part 2): RAID 0 (Striping) – Understanding why disk combinations matter 0

Introduction In part 1 (Understanding the physical performance characteristics of hard disks) we looked at why the physical properties of hard drives affects throughput i.e. more data can be read from tracks on the outer edge of the disk than the inner thus causing less disk head movement. In this article I will show what happens when we start […]

Short-stroking: Understanding the physical performance characteristics of Hard Disks (Part 1) 2

Article Series As part of my thesis for my Business Intelligence masters (see I did a lot of research around Solid State and Hard Disk drives, this series of articles reflects that research. First I’ll talk about the physical properties of hard drives and progress through to its affect on how SQL Server performs […]

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