How big should our guest be? How many cores should we allocate? How much memory? How much storage?
For a two-CPU VM, Vmware found just an 8% CPU overhead.CPUs are constantly getting fasterHow many of you believe that? Well, the reason you don’t believe it is because you’re probably not doing it right.
When C needs CPU power, he’s slowing down A & B.Do we allow A&B to run single-CPU operations on CPU 2 while C runs?
Less is more - single processor everywhere. Always easy to go up if you really need it.Good practice for SQL licensing anyway.It’s not about getting as many CPUs as you can – it’s about succeeding in the virtual environment.Every tick – remove anything that burns CPU, including screensavers
Freed up = balloon driver
It LOOKS like an array to you, but it’s really just a file on another array. Here’s a screenshot…
This is just one volumeProblem is exacerbated with today’s huge hard drivesGotta monitor IO 24/7It’s not just the performance of the drives – it’s also how you ACCESS the drives
Your guest can move from host to host at any timeOther guests can pile on to your hostHost configurations can change without you knowingCPU & memory testing is almost meaningless as long as you’re sharing hosts
How many of you have cable modems or DSL?How much does it cost you per month?I bet you’ve run speed tests to find out how fast it is, right?
Good news is that your SAN admin can change RAID methods, cache settings, all kinds of things to improve performance
We need something to measure with – what runs every day, and we keep a history of it?Backup job times.
Virtualization and SAN Basics for DBAs
VMs, SAN, SQL:The Big Threes<br />Brent OzarQuest Software<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/ektogamat/2687444500/<br />
Never OverallocatevCPUs<br />Less is More<br />Every Tick Matters<br />Minimize CPU Work<br />Don’t Be Strict<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/rsimpson/3832084595/<br />
So What About Memory?<br />Host: 64GB<br />Guest: 16GB<br />Other Guests: 32GB<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/erikthenorsk/3642116265/<br />
So What About Memory?<br />Host: 64GB<br />Guest: 16GB<br />Other Guests: 80GB<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/erikthenorsk/3642116265/<br />
How Hypervisors Cope<br />Host page file<br />Dedupe memory(page sharing)<br />Keep guest OSmemory freed up<br />Learn more inmy bookmarks:http://delicious.com/brento/balloon<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/heartlover1717/208534358/<br />
Never Use Automatics<br />Set SQL Server’s min/max memory<br />Set VMware’s reservation size<br />Use locked pagescarefully<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/nataliejohnson/2419154951/<br />
Which Causes An Outage?<br />New neighbors<br />RAID restripe<br />Drive failure<br />Cable change<br />Firmware change<br />Switch upgrade<br />Controller reboot<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/celebdu/10200825/<br />
Where Will You See Changes?<br />Windows event log<br />SQL Server logs<br />Profiler traces<br />Net Send popups<br />Your dreams at night<br />
Always Be Checking<br />Photo Licensed with Creative Commons From http://www.flickr.com/photos/buro9/298998173/<br />
My 3 Favorite Metrics<br />Physical Disk: Avg Sec/Read and Write<br />System: Processor Queue Length<br />SQL Server Memory: Page Life Expectancy<br />
It’s Not All Bad News!<br />Easier scaling<br />Less firmware outages<br />No leased hardware cycles<br />Easier disaster recovery<br />Easier dinosaur handling<br />
Wrapping It Up<br />Virtualization Nevers:<br />OverallocatevCPUs<br />Use automatics<br />Assume your VM is alone<br />SAN Always’s:<br />Know your neighbors<br />Test first with SQLIO<br />Be checking<br />