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Pyrolistical
Asked: 2009-05-22 14:31:29 +0800 CST

What is faster? A local mechical hard drive or a solid state drive over gigabit ethernet?

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SSDs are rather new, so I couldn't find this information on the Internet.

Would the performance of a local hard drive connected using SATA2 get out performed by a SSD over gigabit ethernet?

In terms of both latency and bandwidth, mechanical hard drives and local networks are very similar.

The SSD would over course be SLC or Intel's MLC. Not a cheap MLC.

EDIT

As for usage, think typical computer user with some multimedia. Let's say its a regular computer with mechical hard drive vs a diskless computer that boots off a USB stick and then loads the OS off a SSD over gigabit

performance hard-drive ssd gigabit-ethernet

7 Answers

  1. This article states 53 MB/sec transfer for 32 GB ssd drives in June 2007.

    In October 2008, Engadget reviewed a SSD drive claiming 235 MB/sec.

    The key difference I have found with SSD drives is that:

    • their seek speed is next to nothing (0.2 msec) vs a 7 to 16 msec seek time on a regular hard drive.
    • in addition to performance not being affected due to heating from moving parts
    • cpu utilization seems to be much lower
    • power utilization is lower

    Based on the above and the fact that solid state is generally always faster than moving parts, I would go with SSD, as long as it wasn't cost prohibitive, and you had a drive that could drive the full capacity of your network gear and the cabling, as well as the computer on the other end being equipped to communicate at full capacity.

    Since we love charts, here's one from the first article. enter image description here

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  2. Best Answer

    Large sequential operations - go with local disk as you'll get 100MBps or so with the right disk and controller.

    Small random operations - more likely to go with the SSD as the 'seek' time will offset the lower bandwidth of 1Gbps Ethernet (plus the encapsulation overhead).

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  3. The number will vary widely if the read/writes are random or if they are sequential and how full the disks are. It will also depend on the specific disk.

    For reference the theoretical maximums are:
    Gigabit Ethernet: 125 MB/sec (you'll have protocol and network traffic to contend with as well)
    SATA2: 384 MB/sec

    Does the read speed of either disk come anywhere close to those theoretical maximums? Most 1TB drives now a day are giving ~90MB/sec read. My gut says the local hard drive but there are many other factors at play that could make the local drive dog slow. (SATA2 drive in a USB enclosure on a USB 1.1 hub for example)

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  4. There is no good way to answer this question. How your applications are using the drives matter a lot more then how computer with the drives are connected to the network. Is your workload mostly writes or reads? Do you have lots of sequential access or random access.

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  5. Reading the original question, this is not an SSD vs Platter issue. NO, it would not be worth it to run an SSD over gigabyte Ethernet. In fact you've got it backwards. The ideal scenario would be SLC SSD for the main OS partition, and then save everything off to a networked HD.

    This will not work the way you envisioned because, while GB Ethernet more then enough to handle the IO demands of a regular PC. It is not sufficient to allow you to really utilize a SSD. My advice save some cash get a WD raptor, while the seek times aren't nearly as good as an ssd. Raptors are time tested, and equally capable of saturating a GB Link.

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  6. SSD has a limited number of writes (but it's getting better).

    A NAS with dynamic memory... Now that's a different story! We just moved a database machine from a DASD to a NetApp filer using 2 (yes 2) 4 Gigabit connections. Our speed is more than 3 times better than DASD. The caching, I/O distribution etc make this thing SCREAM!!!

    The server is about 8 feet from the storage, which makes this affordable. If the servers were outside the data-center, costs would soar for this kind of connectivity, but more affordable solutions do exist for speeds nearly that of DASD.

    If you're moving spreadsheets and Word documents, you wouldn't notice the difference. Databases... They need SPEED!

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  7. I will definitely go with the local mechanical drive.

    Even if someone test it and find the SSD over the network faster, go with the local drive.

    My main argument is that the network connection is SHARED with other network users. That means that if you have several co-worker doing bandwidth intensive operations, your experience will degrade quickly.

    Also, the network latency is something to think about. There is this guy, first name Linus, who wrote a version control system (git). One of his first premise is that even if you have an old and crappy hard drive, it will still be faster than going through the network.

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