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Wednesday, October 24, 2007

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GBM How-To #28 : Speeding up your external USB drive

- Eddie VanDerbeck

How many external USB drives do you have installed? I had to use both hands to count the ones attached to my server. But what's that got to do with mobility you ask? Well, nothing. However, most of us have at least one USB drive attached to your system for backups, storage of media files, etc. This how-to will show you how to milk every bit of performance out of your external USB attached disk drive.

!!!!! DISCLAIMER UPDATE !!!!!

The following How-To is for those that are experienced users and understand the risk of data loss that may result. Please remember to NOT perform this on any system that contains any data you are not willing to lose. I have used this for months on a three systems without issue. An SBS Server (6 drives) , a Vista Ultimate Media Center (3 drives) and on my Lenovo X60 Tablet Docking Station (2 drives). Please note that these systems are adequately protected with power backup AND tape backup systems. Understand that if the power or cabling on any of the attached devices is removed BEFORE the system is shut down or the device stopped, there is a VERY REAL risk of loss of data or drive corruption. Disclaimer stated... here we go.

!!!!! DISCLAIMER UPDATE !!!!!

GBM How-To Series #28 : Speeding up your external USB drive

Write caching is what hard drives use to help them be faster than they could otherwise be. Did I hear someone ask "what is write cache"? Glad you asked. Think of cache like this; data that's normally written to disk by the CPU is first written into a special area of fast memory utilized by the CPU called "cache". During idle machine cycles, the data are written from the cache onto disk. Write back caches improve performance, because a write to the high-speed cache is faster than to normal RAM or a mechanical disk. This does not always apply to newer SSD technology (Solid State Disk) drives where write caching might actually slow performance.

Write caching on external devices that are removed frequently such USB thumb drives this technology is disabled because you could corrupt the file system if data is not successfully written before it's removed. However, devices like external USB hard drives that for the most part are kept plugged in, this is not ~~really~~ absolutely necessary. Remember you MUST maintain power and cabling integrity for this to be safe!

Click on the Start button, then right click on Computer and select Manage.

Click on Device Manager on the Computer Management (Local) menu. Remember you can get back to the defaults by clicking Restore Defaults

Expand the Disk drives group and locate your desired external hard drive in the list.

Right click on the drive and select Properties then on the Policies tab, select Optimize for performance.

REMEMBER that there is a real danger to losing data if a power failure occurs or if the cable is removed BEFORE the write process is completed!

There you have it. Your new and improved speedy external USB hard drive.

Technorati Tags: How-To, External Hard Drive, Optimization

10/24/2007 9:33 AM MST

GBM How-To #28 : Speeding up your external USB drive Comments [3] | Digg This | del.icio.us | Citations

Wednesday, October 24, 2007 10:29:17 AM (Mountain Daylight Time, UTC-06:00)

Eddie, there's a dangerous bit of misinformation in your article here...

"Write caching on external devices that are removed frequently such USB thumb drives this phrenology is disabled because you could corrupt the file system if data is not successfully written before it's removed. However, devices like external USB hard drives that for the most part are kept plugged in, this is not really necessary."

I think you're mistaking the write cache in the operating system with the write cache that may be built into the hard drive. If you enable write caching as you have recommended, then unplug the USB cable (but leave power to the hard drive) you will lose data and corrupt files. The data is buffered in memory, not somewhere on the external drive. If Windows can't put that buffered data onto the drive, the fact that the drive is still plugged in means nothing.

There's a very good reason that write caching is turned off for removable drives. I highly highly highly recommend that your readers NOT do this unless they are willing to lose data because it's very likely that they will.

Josh Einstein

Wednesday, October 24, 2007 11:29:38 AM (Mountain Daylight Time, UTC-06:00)

I see your point Josh; please see my updated disclaimer on this post. If the drive is considered a REMOVEABLE device (ie, there is a possibility that you may remove it) you have an excellent point. Better to leave the OS write cache turned OFF. However, if you can ensure that you will not kick the cables (power OR data) out, or loose power (to your system OR drive), IMHO and experience, there is really no more risk of data loss than on an internal drive. How many times have we all had to improperly shut down our systems for one reason or another by killing the power?

Eddie VanDerbeck

Wednesday, October 24, 2007 10:04:33 PM (Mountain Daylight Time, UTC-06:00)

Well being that it's GottaBeMobile.com, it's probably safe to assume many of the readers would be using laptops or tablets, so even just undocking from a docking station that had an external drive plugged in you could lose data. But it might also be worthwhile to remind them how to properly remove the device using the Windows "safely remove hardware" icon.

With regard to internal drives and write caching, you are very correct. It's way too easy to lose data this way which is why Windows disables it by default. The two settings, to the best of my knowledge, just control the frequency of the cache flushing and size of the cache. So with the first option checked (and the second option unchecked) I presume that it's safer, but not completely safe. Running without any write cache is just too slow. But running with a very delayed cache, while it may speed up performance, leaves you open for more data loss. The only hard drives completely safe would be something like a ReadyDrive capable disk where Vista can use the on-board flash as a write cache.

But aside from that, tablets and laptops are actually the safest to use the optimized write cache because the only way to kill it is to pull the battery or hold the power button.

Josh Einstein

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