Preallocated iSCSI Disk Size Incorrect in OSX

[nbreslow]

Hi,

Problem: Preallocated 200 gb iSCSI drive shows up as 215 gb in OSX Disk Utility.

I am using a DS209+II (latest firmware) with two 1 tb drives in Raid 1 as NAS for my MacBook Pro at work and ran into something strange when setting up an iSCSI disk to be used for a Time Machine backup drive. I setup the iSCSI drive using DiskStation Manager 2.3 as a preallocated 200 gb disk, setup the globalSAN iSCSI initiator 4 beta for OS X, and connected to the iSCSI disk without issue. Once I go into Disk Utility I see that the drive is showing as 215 gb instead of 200 gb. I initialized the drive anyways using 2 partitions - 1 Mac OS Extended (Journaled) 200 gb, 1 Free Space 15 gb. Everything works fine but I wanted to post here to see if anyone had a similar issue? I am just hoping that, over time, the drive will remain stable as it fills up. I want it to get no larger than 200 gb, and in the DiskStation Manager it says 200 gb are all that are being used. Thoughts?

Thanks,

-Nick Breslow

[netsrac]

Pretty sure that you are running Snow Leopard...

This was one of the big changes Apple did when going from Leopard to Snow Leopard. Instead of using multiples of 1024 for calculating drive space, they are now using 1000 and a multiplier.

So your 200 GB under Linux (Synology) are:

200 * 1024 * 1024 = 209715200 bytes

Snow Leopard now simply divide this by 1000 to get the GBs:

209715200 / 1000 / 1000 = 210 GB

Okay...still 5 GB missing, but I guess this is due to the reason that the drive on the Synology is not exacty 200GB and has been round a bit due to blocksizes.


Hope this helps...Netsrac

[Zarocq]

You're missing the 5GB because you forgot to multiply with another 1024 to get it in bytes: 214748364800. You were only down to Kbytes.
And then you got 215GByte - counting as 1000 bytes/kilobytes.

[nbreslow]

AHA!

Totally forgot about that - thanks so much. So if I want to get to 200 in Snow Leopard then I should setup a 186.265 in DS Manager. Thanks so much for the responses, appreciate it.

-NBreslow