View Single Post
Unread 02-15-2007, 08:49 AM   #11
blue68f100
Thermophile
 
blue68f100's Avatar
 
Join Date: Jul 2005
Location: Plano, TX
Posts: 3,135
Default Re: Attention All 4100 owners

Quote:
Originally Posted by bsmith
Not to ask a stupid question but, what point is there in adding a resister in series with a ferrite bead. Generally an smt ferrite bead has a dc resistance in the tenths of an ohm. I could see maybe adding a small cap to it to further block unwanted frequencies. BTW I have a 4100 70715048-001 without the mods.I suppose I will try and find a couple of 10ohm SMT resistors in my stash and add them as I'm getting ready to go to 4x160G from 4x30G
Will try to explain why it is needed. The resister is used to slow the response of the coils or damper them. Apparently with larger drives it was not settelting down. Like they were over driving the coils. Causing scatter, which in turns corrupts the raid5 array.

Recovery is very difficult in this condition because the drives are not put the data on the disk where it is suppose to be.

When you are trying to sync 4 drives timing is critical. Even a drive reallocating a bad sector with smart tech can cause problems. It best if you can run a utility to check the surface and have it update the table prior or soon after put in service. This way most of the bad sectors will not be use.
__________________
1 Snap 4500 - 1.0T (4 x 250gig WD2500SB RE), Raid5,
1 Snap 4500 - 1.6T (4 x 400gig Seagates), Raid5,
1 Snap 4200 - 4.0T (4 x 2gig Seagates), Raid5, Using SATA converts from Andy

Link to SnapOS FAQ's http://forums.procooling.com/vbb/showthread.php?t=13820
blue68f100 is offline