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NAS too slow? Try DAS

Bill Meade

March 16, 2007

Introduction

I originally got sucked into the wonders of RAID storage by a friend who needed a better way to store thousands of digital images accumlated through his business. I helped him out by putting together a NAS not unlike the one I described in Build a Cheap and Fast RAID 5 NAS. Since that article, I've fielded numerous inquiries about DIY RAID NAS building, with many of them focused on pushing the performance envelope to infinity and beyond!

But if you really want fast storage, logic would dictate that you go with direct attached storage (DAS). It's not just the bandwidth of the buses that can make DAS leave NAS in the dust, but the fact that DAS doesn't incur the performance hit from network filesystem protocols that burden NAS.

But what DAS giveth, it also taketh away. Because while DAS provides gobs of performance for the computer that it's attached to, anyone else wanting access to those files will be thrown back to relatively stone age speeds when a network-shared folder is created—no matter which OS you use.

The end goal of this article is to provide a sense of the speed differences of DAS vs. NAS. The idea is that armed with this knowledge, you'll be able to better judge the speed vs. convenience trade-off that you are considering. The DAS that will be used for comparison is Norco's DS-500 (Figure 1). My adventures with the DS-500 were, uh, interesting, enough that you'll also get a review of it, too.

Norco DS-500

Figure 1: Norco DS-500

Norco makes a family of storage hardware products that are mostly physically larger than the DS-500, which is a five drive desktop external SATA RAID system. The DS-500 is 6.8" x 9.5" x 11" in size and comes in a box that is 1/2 to 2/3 the size of a computer case box (Figure 2). I found the DS-500 for as low as $451 (without drives) delivered on the net.

DS-500 box

Figure 2: DS-500 box

So the direct attached 5-drive array compares favorably in cost to many NAS RAID array products such as the Synology CS-406 that I reviewed last year (and have been thinking of buying ever since, even though it is not the fastest NAS on the block). The CS-406 without any drives is approximately $570 delivered and it holds 4 drives.

Inside the box (Figure 3) is the hard drive case, an external PCI-X SATA adapter card, an installation disk, an external SATA cable, a power cable, packet of bolts, and a Phillips screw driver to install one of the bolts in the PCI-X adapter card to hold it in. I think that Norco is also assuming that the end user will probably need bolts to install hard drives into the drive trays that go in the external drive cage. The system I was provided for testing included five 250 GB hard drives, so I did not use the extra bolts provided.