Building an Intel Core i7 based computer - Storage

Disks fail more often than one can imagine. Because my data is the most important part of my computer my main objective is data safety so I’ll go for RAID 1 – disk mirroring that guarantees data integrity even if one of the two disks fails. Heck, I wouldn’t even miss a working day in such case – I’d just work with one disk until the damaged one gets replaced. RAID 1 is expensive because it mirrors the data – you’ll need two disks for the same data, however, the data will be redundant and furthermore RAID 1 reads data almost as twice faster than a single disk solution, write process is a bit slower compared to the single disk solution though. Another benefit of RAID 1 is possibility of using a motherboard-integrated RAID controller (which uses few CPU cycles, yet one won’t notice it on 4-core CPU) without any performance loss. RAID 5 is out of question because of really slow writes and requirements for an (expensive) add-on controller (although there are integrated controllers that handle RAID 5 but they will make it even slower). Add-on controllers have additional features such as memory cache (I’ll just use cheaper OS caching) and an option for batteries that will save the data in case of power failure (I will use an UPS to power my computer anyway – no need for those batteries).

Secondary objective is performance/price ratio. These days storage devices are the main performance bottleneck because they are relatively slow and computer often accesses them. They are even more important when you ran out of RAM (hope not, but it can happen) – then the page file swapping party begins. So the main goal is to get as good price/performance ratio as possible.

First, there are two choices: hard disk (HD) or solid state drive (SSD). I’ll pick HD option because SSDs are:

  • unproven new technology (in the long term)
  • usually slow for writing operations (they are improving though)
  • very pricey

So, I have three choices with HD technology:

  • SATA (mainstream)
  • SAS

SAS drives are very expensive, relatively small and I am not sure whether their faster speed would bring enough benefits in the performance/price sense. Furthermore they require additional SAS controller which isn’t cheap either. I think that SATA technology is far better for me. Every motherboard has an integrated SATA controller, better motherboards support RAID 1. But which drive? I’ll go for WD Velociraptors because, albeit they are more expensive, they are considerably faster than standard 7.200 RPM disks. Interestingly, Velociraptors are 2.5” disks packed in 3.5” chassis (no, they can’t be mounted in a laptop).

I bought a pair of Western Digital Velociraptor WD3000HLFS 300GB 10.000 RPM drives from mimovrste.com for 2 x 246,79 Euros.

See other relevant posts:

Introduction
CPU cooler
The goal
Power Supply Unit
Memory

Comments (6) -

  • Marc Greiner

    2/25/2009 4:57:30 AM | Reply

    Hi Miha ;

    Thanks for sharing all this, I really enjoy reading it.

    I chose RAID 0 + monthly complete backup with Acronis. I tried once the Vista Complete Backup Tool but it fails to restore on disks of different size or on a RAID system, so it is to forget totally... Acronys did exactly this to me without asking any question.
    I use an external USB hard drive for the backup.
    I also copy daily every important data (source code, documents, etc.) to an usb stick with winzip and its command line in a batch.
    The most I can loose is a day of work or a month of small bits and pieces here and there, but I get faster write access with a RAID 0 than with a RAID 1.

  • Miha Markic

    2/25/2009 5:19:41 AM | Reply

    Hi Marc,

    Glad that you like it Smile. Yup, you are doing backups, not redundancy. I am using Windows Home Server for daily backups - it has a fabolous storage engine and it is fast.

  • Marc Greiner

    2/27/2009 12:22:35 AM | Reply

    Miha wrote:


    I am using Windows Home Server for daily backups - it has a fabolous storage engine and it is fast.

    ------------


    Well, I guess that this could be another good future blog topic from you...


    Have you tried to restore such a backup on a RAID disk of a different size? New disks seldomly come in the same size than the broken disk and sometimes you even would need to restore on another hardware (motherboard, etc...).

  • Miha Markic

    2/27/2009 12:55:25 AM | Reply

    Hi Marc,

    No, I haven't tried yet to restore on different configuration - I successfully restored it when RAID went beserk, curtesy of Intel drivers and iTunes (go figure). However, WHS lets you extract the image as files like you do with Windows Explorer - so I feel safe Smile

    I don't think that disk size matters either because if one fails then you have to buy another one at least as big (or bigger) - the same model with same firmware is prefered. Then you configure RAID array with this new disk at BIOS level (before even doing restore). The good news is that it isn't wrong to use a bigger disk - the only drawback is that you get some additional spare place on the bigger disk (you might use it by creating another partition however, it isn't very wise in terms of performance).

  • Miha Markic

    3/23/2009 1:06:07 PM | Reply

    Hi Marc,

    Looks like they are quite silent. I don't think they are more noisy than standard 7.200RPM disks. The noise, as you found out, depends on different factors and it is subjective unless it is measured in lab conditions, etc.

Loading