UPS for raid? at DVinfo.net

Paul Mailath · March 14th, 2010, 09:27 PM

I've read that a UPS is recommended with a raid configuration but I'm not sure why.

when the power goes off - with a single drive you lose any data that is being written to disc but files on the disc are intact.

with a raid configuration surely its' the same, even if the data is spread over 3 or 4 drives you would still only lose any files currently being written to disc

or am I wrong?

Shaun Roemich · March 14th, 2010, 09:30 PM

Heads crashing into platters would be one good reason.

Robert Lane · March 15th, 2010, 01:03 AM

A UPS should be used for *any* system and it's mission-critical components to protect against power failure. The main CPU, main monitor, RAID enclosures you name it. If you don't use one it's like not wearing a seatbelt; it's not a question of *if* you'll have a power outage it's when. It's cheap insurance - get one and rest easy.

Shaun Roemich · March 15th, 2010, 09:58 AM

As well, a UPS provides "top up" benefits for brownouts when voltage drops but doesn't completely blackout.

My UPS reported 167 "events" in a year and a half at my old home and zero so far in the past 8 weeks since it has been online in Vancouver.

Dean Sensui · March 15th, 2010, 04:10 PM

Paul... If the file being written to the disc happens to be the directory, then it'll really mess things up on both drives.

As others have said, if it's important, protect it.

A hundred bucks is cheap compared to the potential of losing hours of hard work, and the additional hours it would take to get it all back working again.

I got a Tripp Lite recently from Costco to replace an aging UPS.

Mike Calla · March 15th, 2010, 09:04 PM

A UPS is REALLY good cheap way to cure poor AC quality.

Kirk Candlish · March 15th, 2010, 11:53 PM

All of the above are true provided the UPS has automatic voltage regulation and you're truly running off the battery at all times. Cheap UPS units are auto switching and the battery only comes online in the case of a power outage. They don't handle brownouts and may not clamp an instantaneous voltage spike. You get what you pay for.

Mike Calla · March 16th, 2010, 09:26 AM

bad power here, a massive amount of construction tapping into the local power lines. i had sudden shut downs, usb thumb drive ejects, non starts, usb audio preamp and monitoring device that would unmount and I'd need to plug in again. Funny, NEVER had a blackout here, or really even noticeable brown outs, but the power is crap.

I have a cheap APC 650 UPS, cured all the above problems, doesn't work on battery but been fine.

Richard Hogben · March 17th, 2010, 10:42 AM

Quote:

Originally Posted by Mike Calla

I have a cheap APC 650 UPS, cured all the above problems, doesn't work on battery but been fine.

Same reason I have UPS on all my electronics. Not for if there is a blackout, but just because a little power conditioning goes a long way to keeping happy gear.

Richard Hogben · March 17th, 2010, 10:49 AM

Quote:

Originally Posted by Paul Mailath

I've read that a UPS is recommended with a raid configuration but I'm not sure why.

It would also depend on the raid configuration.

If the drives are striped (raid 0) and something bad happens all the drives will be affected. Even if the drives are mirrored (raid 1) they could all have corrupted data written to both disks. Most of these raid setups will protect you in the case that you have a drive failure, but not against power outages and corrupted data written to the discs.

UPS is a good idea.

March 14th, 2010, 09:27 PM	#1
Paul Mailath Trustee Join Date: Dec 2006 Location: Central Coast - NSW, Australia Posts: 1,610	UPS for raid? I've read that a UPS is recommended with a raid configuration but I'm not sure why. when the power goes off - with a single drive you lose any data that is being written to disc but files on the disc are intact. with a raid configuration surely its' the same, even if the data is spread over 3 or 4 drives you would still only lose any files currently being written to disc or am I wrong? __________________ Cheers - Paul M. www.perbenyik.com

March 14th, 2010, 09:30 PM	#2
Shaun Roemich Inner Circle Join Date: Sep 2002 Location: Vancouver, British Columbia (formerly Winnipeg, Manitoba) Canada Posts: 4,088	Heads crashing into platters would be one good reason. __________________ Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/

March 15th, 2010, 09:58 AM	#4
Shaun Roemich Inner Circle Join Date: Sep 2002 Location: Vancouver, British Columbia (formerly Winnipeg, Manitoba) Canada Posts: 4,088	As well, a UPS provides "top up" benefits for brownouts when voltage drops but doesn't completely blackout. My UPS reported 167 "events" in a year and a half at my old home and zero so far in the past 8 weeks since it has been online in Vancouver. __________________ Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/

March 15th, 2010, 04:10 PM	#5
Dean Sensui Inner Circle Join Date: Oct 2001 Location: Honolulu, HI Posts: 2,054	Paul... If the file being written to the disc happens to be the directory, then it'll really mess things up on both drives. As others have said, if it's important, protect it. A hundred bucks is cheap compared to the potential of losing hours of hard work, and the additional hours it would take to get it all back working again. I got a Tripp Lite recently from Costco to replace an aging UPS. __________________ Dean Sensui Exec Producer, Hawaii Goes Fishing

March 15th, 2010, 09:04 PM	#6
Mike Calla Major Player Join Date: Sep 2003 Location: Shanghai Posts: 344	A UPS is REALLY good cheap way to cure poor AC quality. __________________ boxoutsidemedia.com

March 15th, 2010, 01:03 AM	#3
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Mesa, AZ Posts: 2,826 Images: 15	A UPS should be used for any system and it's mission-critical components to protect against power failure. The main CPU, main monitor, RAID enclosures you name it. If you don't use one it's like not wearing a seatbelt; it's not a question of if you'll have a power outage it's when. It's cheap insurance - get one and rest easy.

March 15th, 2010, 11:53 PM	#7
Kirk Candlish Regular Crew Join Date: Feb 2004 Location: Southern, CA Posts: 198	All of the above are true provided the UPS has automatic voltage regulation and you're truly running off the battery at all times. Cheap UPS units are auto switching and the battery only comes online in the case of a power outage. They don't handle brownouts and may not clamp an instantaneous voltage spike. You get what you pay for.

March 16th, 2010, 09:26 AM	#8
Mike Calla Major Player Join Date: Sep 2003 Location: Shanghai Posts: 344	bad power here, a massive amount of construction tapping into the local power lines. i had sudden shut downs, usb thumb drive ejects, non starts, usb audio preamp and monitoring device that would unmount and I'd need to plug in again. Funny, NEVER had a blackout here, or really even noticeable brown outs, but the power is crap. I have a cheap APC 650 UPS, cured all the above problems, doesn't work on battery but been fine. __________________ boxoutsidemedia.com