SSD (Raid 1) vs SAS (Raid 10) Sql Server Hardware Recommendation?

Question

Our current SQL Server Machine (which is about 6 years old):

Box: Dell 2900
CPU: Xeon 5160 Dual Core
RAM: 4GB
HDD: 6x 15k RPM SAS drives in raid 10

Since it's 6 years old, the drives have been spinning for 6 years straight which is making my employer nervous about the life of the drives. We are considering buying, or upgrading our current server. Does my employer have a rational fear, or should the drives last another few years? (they aren't really easy to find anymore, but we do have a hot spare drive inside the computer on standby, and a hot spare server with the same drives in it)

The idea is to either get another 6 SAS drives to run in RAID 10 or to consider getting two SSD (SLC) drives in raid 1. Aside from cost, is there any reason to opt one way or another?

Is it worth upgrading the server in order to get a new CPU and RAM? Our SQL server's CPU generally doesn't peak over 10%. It runs a medium traffic website and internal business apps, but nothing crazy in terms of usage.

Answer 1

From a disaster recovery, performance and power consumption point-of-view, I'd upgrade ASAP. You can't predict hardware failures, so it might be your disks, the PSU, the motherboard or some other component.

I tend to go by a rule of thumb that says to upgrade professional setups at least every 3 years because performance and power effeciency has usually doubled in that time. Might be hard to find spare parts, too. If your PSU or motherboard dies, how quickly can you restore service? Did you test this? Is the timeframe acceptable for the business?

An awful lot has happened in the last 6 years. You'd have to look really hard to find a new Xeon-based systems that's slower than what you already have.

If your entire database can fit in 4GB or 8GB RAM, you'd benefit greatly from a new CPU and a gigabit network interface.

Do you have any sort of monitoring on this system? Are the disks even moving, except for writing data (which can't be a lot if there's only 2GB of data after 6 years) and access logs?

For what it's worth: Modern SSDs can do insane amounts of writes and the myths from 15 years ago no longer apply. SSDs wear just like mechanical drives do, they're just much faster and reading and writing data. Not sure you have enough data in your database to feel much performance difference, though.

Answer 2

First question

Does your database fit into memory?? As in the actual indexs+data size?? This will answer your need for RAM...

Second question.. What type of read/write mix do you have.. This is where ssd's win and lose..

i setup a DB that had 20% total (nightly) writes and 80% (daily) reads with SSD's and it was FAST.. Try reversing those numbers and watch SSD's lose to 15k SAS disks..

Hope this helps.. :D

Answer 3

The optimal replacement period for Intel hardware is generally between 3 and 4 years. Beyond that, you're rolling the dice in terms of reliability (especially for software embedded in hardware), parts availability and the speed of restoring service in the event of a failure.

You don't have a performance issue, since you're happy with the old server, so I'd look at replacing the system with a system big enough to consoliate other servers with a virtualization solution, and configure RAID 10 storage to improve overall reliability and performance.

Frankly, if your employer is pushing you to invest money into an asset that depreciates as quickly as a computer, there is a serious lack of clue going on there that is kind of scary to me. A better idea might be to look at a "Cloud"/hosted solution for your database application, where a managed service provider is managing the service for you.

Answer 4

There's a reason you're asking this question about a replacement for a six year old machine, go with the R10 solution, the SSDs will be dead long before 2016 ;)