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I am erasing my internal hard drive and reinstalling the system before giving my 24" iMac (Early 2009) 3.06GHz, 640 GB HD.
How long will it take to erase the drive using Disk Utility's Most Secure option?
iMac (24-inch Early 2009), OS X Yosemite (10.10.2), Canon PIXMA MP600
I found one estimate, based on a test with a 500 GB External Drive connected with Firewire 800, which took 18 hours 22 minutes for a 7-pass erase, yielding an estimate of 0.314 minutes per GB. My 640 GB drive might then take nearly 24 hours.
At that rate, even three passes would take over 10 hours.
That's way too long. I found another article arguing that one pass was sufficient and that anything more was overkill.
I am leaning in favor of on pass at between three and four hours.
I found one estimate, based on a test with a 500 GB External Drive connected with Firewire 800, which took 18 hours 22 minutes for a 7-pass erase, yielding an estimate of 0.314 minutes per GB. My 640 GB drive might then take nearly 24 hours.
At that rate, even three passes would take over 10 hours.
That's way too long. I found another article arguing that one pass was sufficient and that anything more was overkill.
I am leaning in favor of on pass at between three and four hours.
FWIW. I have never seen any published information as to the time required per MB for using Disk Utility's secure erase methods. For anything other than the single-pass methods, it would be best described as "an extremely long time."
Are you sure that someone really really is interested in what is on your disk, and has the technical know how and equipment to extract deleted files?
If not: just do a partition/erase or an simple erase.
If yes: I once did a 3-pass erase on a 500GB HD and stopped it the next morning before it was ready.
Note: If the disk is a SSD, just erase, even deleted files will disappear after a while, because of the wear Levelling/GarbageCollection in the disk controller.
The information is on pc.net. Here is the URL:
How long does it take to complete a 7-pass erase on a hard disk?
I did a single pass secure erase on the 640 GB internal hard drive. On my 24" early 2009 iMac, with a 3.06 GHz processor and 4 MB of RAM. The erase progress box indicated that the erase would take 1 hour and 30 minutes. I did not watch it until the end of the erase but, at the rate it was progressing, I would estimate that it took less than 2 hours to complete.
To answer another user's remark, I don't know how interested anyone might be to uncover my data, and it is unlikely that they would have the skills and tools necessary to do it, but better spend a little computer power to avoid finding out the hard way. It took very little of my time, since I started the secure erase just before I went to sleep.
My thanks to all who participated in this discussion. Perhaps we all learned something from it.
Some remarks about the text you posted the link of:
"....connected via Firewire 800, using Apple's Disk Utility. I began the secure erase at 12:13 AM and the process completed at 6:35 PM the same day. Since the actual formatting of the drive takes less than a minute with Apple's Disk Utility, the disk formatting time is negligible. Therefore, the 7-pass erase on the 500 gigabyte drive took 18 hours and 22 minutes (1102 total minutes)."
1. I think there is a difference between FW800, USB2,USB3 and (internal) Sata1, Sata 2 and Sata3.
2. from 12:13am to 6.35pm the same day is NOT 18 hrs and 22 mins.
1. I think there is a difference between FW800, USB2,USB3 and (internal) Sata1, Sata 2 and Sata3.
Yes. Of course you are right. I was just trying to find some kind of benchmark. As I was going to use an internal drive, I expected my secure erase to be faster.
2. from 12:13am to 6.35pm the same day is NOT 18 hrs and 22 mins.
Ah... Yes it is. From 12:00 a.m. to 6:35 p.m. is 18 hours, and from 13 minutes to 35 minutes is 22 minutes.
Thanks for the additional information. Care to share where you got that information from?
That is usually sufficient.
I've done this before it takes about one and a half days for the most secure option on snow leopard for a 500gb hd for a 2008 iMac (10.6.8) and about 19 hours on a 2010 iMac (10.12.3)
Thank you! Much appreciated.
::::12:00 a.m. to 6:35 p.m. is 18 hours....
the article explicitly says "on the same day"...
But 18 hrs is likely and 6 hrs is not for an erase....
How long does a Secure Erase take
