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Stop Analyzing iowait: Why Local SSD Storage is the Only Upgrade That Matters in 2011

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The "Cloud" is Just Someone Else's Slow Hard Drive

Let’s be honest with each other. If I see one more hosting provider selling "Unlimited Cloud Storage" that turns out to be a congested 7.2k RPM SATA array sitting behind a choked NFS mount, I’m going to lose it. We are in 2011. We have moved past the era where waiting 500ms for a disk seek is acceptable.

I recently spent three sleepless nights debugging a Magento installation for a client in Oslo. The site was crawling. The load average was 25.0, but top showed CPU idle at 90%. If you've been in the trenches, you know exactly what that means: iowait.

The client was on a "premium" cloud platform using a centralized SAN (Storage Area Network). One noisy neighbor on that same storage array was running a backup script, and my client's database was effectively frozen waiting for disk access. This is the reality of shared storage.

The SSD Revolution: Not Just for Laptops Anymore

The single biggest bottleneck in server performance right now isn't RAM and it isn't CPU frequency—it's Disk I/O. While spinning platters (HDDs) can push decent throughput for large files, they are terrible at the random read/write patterns generated by MySQL or Apache logs.

This is where Solid State Drives (SSD) change the game. We are seeing random I/O performance jumps of 50x to 100x compared to 15k SAS drives. In a VPS environment, this low latency is non-negotiable.

Diagnosing the Bottleneck

Don't take my word for it. Log into your current server (CentOS 5 or 6) and run this:

iostat -x 1

Watch the %util and await columns. If %util is near 100% and your await (average wait time for I/O requests) is spiking above 10-20ms, your disk is the problem. No amount of PHP caching or Nginx tuning will fix a physical limitation of the drive head seeking across a platter.

Virtualization Matters: OpenVZ vs. KVM

Another dirty secret in our industry is the abuse of container-based virtualization like OpenVZ. It allows providers to oversell resources aggressively. If the kernel is shared, so are the limitations.

At CoolVDS, we have standardized on KVM (Kernel-based Virtual Machine). With KVM, your kernel is yours. Your memory is allocated effectively. And most importantly, when combined with our local SSD arrays, your I/O isn't fighting for air against a hundred other users. It's the closest you can get to bare metal without the dedicated server price tag.

Pro Tip: If you are running MySQL 5.5 on KVM, ensure you change your I/O scheduler from `cfq` to `noop` or `deadline` inside your guest VM. Since the host handles the physical sorting, the guest shouldn't waste cycles re-ordering requests.

The Norwegian Advantage: Latency and Legality

For those of us deploying for Nordic audiences, physics still applies. Hosting in Frankfurt or London adds 20-40ms of latency compared to hosting right here in Norway. Connecting to NIX (Norwegian Internet Exchange) in Oslo ensures your packets take the shortest possible path to your users.

Data Sovereignty in 2011

Beyond speed, we need to talk about the Personopplysningsloven (Personal Data Act). With the US Patriot Act casting a long shadow over data hosted by American companies, keeping your data on Norwegian soil is the only way to guarantee compliance with Datatilsynet's strict standards. You do not want to explain to a client why their customer data was subpoenaed by a foreign entity because you wanted to save $5 a month on hosting.

The Verdict

Stop optimizing code for slow hardware. If your iostat looks grim, it's time to move.

CoolVDS offers KVM instances running on RAID-10 SSDs directly in Oslo. We don't oversell, and we don't hide behind "Cloud" marketing fluff. We give you raw root access, low latency, and the I/O throughput your database actually needs.

Ready to kill iowait? Deploy a CentOS 6 SSD instance on CoolVDS today and experience the difference of local flash storage.

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