Hello, I want to use an external hard drive for backups. I already have an internal drive in an enclosure, but apparently they don't spin down, and external drives do.

I'm looking for advice on which brands or models generally give the most freedom, i.e. I can change the file system freely from what they ship, while still maintaining the features that an external hard drive brings, mainly, the spin down.

Looking for the 500GB range, around there. USB is a must, eSATA will be a nice to have.

- rmjb

I don't understand why you are concerned about the drive spinning down. The only things I can think of are heat generation, power consumption, hard drive life.

Most external backup drives are not on all of the time but if you have scripts that run at night and have to leave the external drive on overnight, I suppose heat and power consumption might be issues. If not, most people would just turn the drive on and off as needed to do backups. Turning the external drive off is probably a good policy anyway as it prevents anything from accessing the drive and possibly screwing up your backups when the drive is not being used for backups.

Power consumption on a single hard drive is probably minimal so I don't see that as a concern except on mobile systems running off of battery power.

Excessive heat and it's effect on hard drive life are usually mentioned as a concern for external hard drives which presumably would be mitigated by spinning the drive down. But this problem is better solved by either turning the backup drive off when not in use or getting a high quality enclosure or external hard drive with an internal cooling fan rather than the passive cooling on the cheaper units. I know there are many complaints on the maxtor external units that are passively cooled and maxtor recommends that you do not leave them on all the time. I suspect that the spin down feature on the external hard drives you mentioned are just a cheaper way to deal with the excessive heat in an external enclosure rather than put in proper cooling. Apricorn makes very nice fan cooled enclosures which I've used with great success which I think is a better solution than spinning the drive down.

As far as extending hard drive life, I don't think there is any good evidence that spinning the drive down increases hard drive life. In fact some argue that the main mechanical wear on a hard drive comes from spinning the drive up and down and that hard drive life is negatively impacted by spinning the drive down and up excessively, i.e. it's better to leave the hard drive running all of the time. That debate has gone on for years and is unlikely to be settled anytime soon. The point is that there is no definitive evidence one way or the other on the issue.

Thanks for the input. The main concern about spin down is hard drive life and not so much heat generation or power consumption.

As it is, I'd expect one backup a day, at night that may last a couple hours (tops), so for ~22 hours the drive is not needed to be spinning. Also I don't want to rely on me turning the drive on and off.

I've heard the back and forth about spin down and wear and tear, but I want to believe that spin up, 2 hours of use and spin down will cause considerably less wear and tear on a drive than 24 hours of continuous spinning. So all in all I'd still want to get an external drive as opposed to what I have now, an external enclosure.

Thanks for the advice on staying away from the Maxtors and looking for active cooling. Anyone else have advice or experience with external drives they'd like to share?

- rmjb

Active cooling seems to be hard to find in an external usb drive. I suppose the reason is that it increases the size of the package and increases the cost of the package. I recently deployed a Seagate 320 Gig PATA drive in a Lantec NexStar-3 case and it seems to work well enough, with very little heat generated. The case is aluminum so if the drive was heating much I'd feel it pretty quickly on the outside, and I don't.

The pre-built USB drives that I investigated all contained standard internal drives in an enclosure. Also there seems to be a handful of standard chipsets used for the USB to PATA (or SATA) interface. So the drive will only spin down (I think) if the particular drive supports that and if the chipset will do it. I didn't look into that because I leave all my drives running 24/7/365, though I do occasionally turn off this USB drive.

The reason I assembled my own rather than purchase is because you don't know what you'll get for a drive in a prebuilt unit; some of them are using IBM (now Hitachi) Deskstars - perhaps the worst PATA drive ever made. Others are using Maxtors. I am not a fan of Seagate PATA, but with all the mergers and sales of HD manufacturers, they look to be one of the best these days - and they now are offering a 5 yr warranty so they presumably have faith in their current generation product.

In any case, since it is an ATA drive (I use SCSI internally - faster and far more reliable), I won't use it for anything critical and if it dies I'll just hit it with a hammer and go get another one.

I agree with you on your preference for external enclosures over the prebuilt external hard drive units, if for no other reason than warranty considerations. The prebuilt units generally have very limited one or two year warranties. However, if you stick a standard drive in an external enclosure, you get the 3 to 5 year warranty that comes with most hard drives these days.

Usually the drive manufacture has a utility to handle the drives features. Among them is (as I recall) a powersave spindown option. I think the changes are some sort of flash arrangement because they survive the drive being unhooked for extended periods.

When the drive is configured in a USB enclosure, the interface is handled by the USB to PATA (or SATA) converter and you can't use any manufacturer utility to control the drive.

At least, I can't access and control SMART on my seagate drive because the cypress logic USB chipset evidently doesn't support it, and when queried the drive reports itself as a cypress logic device. I also can't access the drive using the Seagate tools.

Yes, but you can pull the drive out, hook it up to you regular pata, set the program and then return it to the enclosure. The changes "stick".

Wow a lot of discussion, and LQ didn't notify me of more responses. I'll look into setting any sort of spin down option on the drive I'm using now. Still want to upgrade to a 500GB or something in that range, and possibly an enclosure with eSATA to get more "native" access to the drive.

Thanks for all your inputs.

- rmjb

Sorry for late arrival on this thread, but I have only just been looking into this. I've been using a Nexstar 3 with 200Gb IDE Seagate for a while and wanted to purchase another larger disk.

I second the above remarks about heat dissipation. The hefty aluminium Nexstar box seems to work OK, and gets just warm to the touch, even during heavy data transfer.

A good reference for spinning down USB disks under linux is this page:

http://www.nslu2-linux.org/wiki/FAQ/...wnUSBHarddisks

Although it discusses the Linksys NSLU2 NAS a lot of it is generally applicable. I was able to spin-down the Nexstar/Seagate using

/usr/bin/sg_start 0 --pc=2 /dev/sde

(sg_start is in the Debian sg3-utils package). The same page also has some scripts for using this in conjunction with disk activity tests.

If a disk is shared around a network, so has to be available 24/7 but might only be used occasionally, I would think this would be well worth doing. I ended up buying another Nexstar/Seagate for this reason. Hope spin-down still works.

Perhaps other USB HDs work also.

new and cant find "new thread" but I have a question.
I installed a maxtor 250 gig hd usb. I have an emachines 40 gig [internal] running windows xp home.
my question is, how can I install anything from a disk and have it install onto the external and use that as the use platform rather than having it automatically install onto my tiny 40 gig hard drive the pc came with?
I can download files to the external, but cant install anything from disk [like games etc] to the external as no options are offered to do so. any ideas, work arounds, something I am doing wrong?