Recommended SD card class for NAS server

[newbiee]

Hello,

I would like to create a simple NAS server from Raspberry PI Model B, rev2. I have a spare 4 GB MicroSD card class 4 with SD Adapter. There is a lot of discussions to buy a higher class card for RPi.

Will there be theoretically any significant diference in data transfer speed from attached 2,5" USB HDD to network using RPi with class 4 microSD card and class 10 SDHC card?

Thank you!

[SirLagz]

If all your data is on the USB hard drive, then there will be no difference whether the OS is on a Class 4 or Class 10 SD Card.
What would be better though, is to have the OS on the USB Hard drive as that would speed things up a bit more than the SD Card

[newbiee]

Ok, so I won't need SD card at all? What if the external harddrive with system on it loses power? Can it somehow damage the RPi?

[RaTTuS]

1) you will need an SD card to boot the RPi [you can have the rootfs on the USB HD but you still need the SD Card]

2) not likely to damage the RPi if the HD has a power loss though you could end up with a corrupted file system ...