Entries Tagged as 'Network Attached Storage (NAS)'

Compression

There are two distinct features that Windows Server 2008 outshines Linux on; and both are centric on compression.

For a very long time Microsoft has supported transparent compression as a part of NTFS; you can designate on a file-by-file or directory level what parts of the file system are compressed by the operating system (applications need do nothing to use compressed files).  This feature was probably originally intended to save the disk foot print of seldom used files; however, with the explosive growth in computing power what’s happened is that compressed files can often be read and decompressed much faster from a disk than a uncompressed file can.  Of course, if you’re modifying say a byte or two in the middle of a compressed file over and over, it might not be a good idea to mark it as compressed — but if you’re basically reading the file sequentially then compression may dramatically increase the overall performance of the system.

The reason for this increase is easy to understand; many files can be compressed ten to one (or better), that means each disk read is reading effectively ten times the information, and for a modern, multi-core, single-instruction/multiple-data capable processor to decompress this stream of data put no appreciable burden on the processing unit(s).

Recently, with SMBv2, Microsoft has expanded the file sharing protocol to be able to transport a compressed data stream, or even a differential data stream (Remote Differential Compression – RDC) rather than necessarily having to send every byte of the file.  This also has the effect of often greatly enhancing the effect data rate, since once again a modern, multi-core, single-instruction/multiple-data capable processor can compress (and decompress) a data stream at a much higher rate than most any network fabric can transmit the data (the exception would be 10G).  In cases of highly constrained networks, or networks with extremely high error rates the increase in effect through put could be staggering.

Unfortunately, Linux lags behind in both areas.

Ext4 does not include transparent compression; and currently no implementation of SMBv2 is available for Linux servers (or clients).

While there’s no question, what-so-ever, that the initial cost of a high performance server is less if Linux is chosen as the operating system, the “hidden” costs of lacking compression may make the total cost of ownership harder to determine.

Supporting transparent compression in a file system is merely a design criteria for a new file system (say Ext5 or Ext4.1); however, supporting SMBv2 will be much more difficult since (unlike SMBv1) it is a closed/proprietary file sharing protocol.

Originally posted 2010-07-11 02:00:49.

Promise NS4300N NAS (Update)

Looks like Promise has “fixed” the issue with Seagate 1.5TB drives in the NS4300N NAS…

They’ve replaced Compatibility List NS4300N_SR5_Compatibility_List_v1.0-20081031.pdf with NS4300N_SR5_Compatibility_List_v1.0-20081126.pdf on their support web site — the never revisions of the V1.0 Compatibility List omits the Seagate 1.5TB drive (interesting that they choose to call it V1.0 rather than V1.1 and remove the previous V1.0 list from their web page)… but the firmware release notes still contains the statement that they’ve added support for 1.5TB drives (the only 1.5TB drive I know of is the Seagate).

Promise’s actions are a little suspect… maybe it’s time for a trip over to Alameda’s Small Claims Court…  I’ve retained copies of both versions of the compatibility list as well as the firmware release notes.

And for the record, I have still yet to receive any update to my online support inquiry even though I’ve updated it a number of times with “additional” comments and information; and I’ve called Promise as well.

Originally posted 2008-12-04 22:13:22.

Affordable RAID5 NAS

What a difference a year makes in the storage market… 1TB drives cost under $150 each and Network Attached Storage devices are almost consumer grade.

For about $300 you can purchase a Promise Technology SmartStore NS4300N; put up to four SATA-II hard drives in it and have yourself a fault tolerate storage device that your Windows, Mac, and *nix computers can access via their native file sharing protocols, and manage it via your browser.

The device is derived from an Intel reference design, obviously using Intel technology.  It’s got relatively good performance, very easy to use, and provides anyone with any computer ability a simple fault tolerate storage device of up to 1.5TB (assuming you buy four 1TB drives, and configure it for RAID5).

The technology of this device is very similar to the 16-channel SATA-II RAID5/6 controllers I use in my servers, and the device is somewhat like the Infrant ReadyNAS 600s that I was quite fond of (Infrant was acquired by NetGear, and since then they have been slow to innovate, and maintained what I would say is an outdated pricing model).

There’s a host of reasons beyond just having a fault tolerant storage device that makes something like this a potential buy.  You don’t need to keep computer’s your using on to access data (that can be important if you have multiple computers), you don’t need to worry about backing up your data if you need to re-install your operating system, you don’t need to worry about how to share data between Windows and Mac.

The only downside I’ve found to the Promise verses the Infrant devices is that Promise botched the implementation of spin-down; so the devices keep the drives spinning all the time.  Yeah, it would say a little power to spin down the drives when they weren’t being access (at the cost of taking longer to access data once they’ve spun down), but with today’s drives we’re not talking about that much power — and you have options when purchasing drives of ones that have “green” / high-efficiency ratings.

For both small business, and personal use for those who depend on storage I highly recommend you consider a device like this.

 Promise SmartStore NS4300N

Originally posted 2008-05-15 22:11:53.

Promise NS4300N NAS

I’ve been a reasonably big fan of Promise in the past; their PCI IDE cards worked well, their PCI SATA cards worked well, their 16 Channel SATA2 RAID5 PCIe cards worked fine, and their NAS box seemed like a really good buy.

When I first got the box almost two years ago it worked fine; it had a few issues (like the lack of hard drive spin-down, even though there tech support insisted it had it)… but in general it was a reasonable buy.

A week ago I invested in some 1.5TB Seagate SATA2 drives to upgrade my Promise, their web site indicated that the new firmware that was just released supported the drives so I felt fairly confident in buying them.

Well, the answer is, you can four 1.5TB drives in the box, but you cannot use more than three of them in a RAID array… seems like maybe they never tested it with four drives (wow — a four drive NAS not being tested with four drives).

What happens i that you can build out all the drives, put content on them, but when you reboot — the box complains of file system errors and the only thing you can do is start over — losing the content of your RAID (I hope you haven’t depended on your RAID actually being fault tolerant… if you have you’re SOL).

I figured yeah, this is a bug, I’ll just file a trouble report with Promise and get an ETA on a fix.

I submitted the trouble report (after having to go through way too much of a hassle to setup an account there), got a confirmation email that indicated I’d get a response within one business day…

Let’s see, that’s been almost a week ago — and I don’t have an ETA on a fix, I don’t have any response from them (not even one that says that they’re looking into it — aware or it — or anything).

Let’s face it, if a vendor can’t meet the low-bar expectations they’ve set by actually providing a reply within one business day, what confidence should I have in them that they will ever be able to actually fix the problem and maintain reasonable quality.

All I have to say is that I’m glad my last two RAID controllers came from one of Promise’s competitors — and I guarantee you my next RAID controllers and NAS boxes will likely not come from Promise!

Originally posted 2008-11-20 12:00:04.