By default, the MTCDP mounts the SD card using the sync mount option. This causes all writes to be flushed to the physical card immediately. This can increase write times but allows the writing application to know that the data is on the card when it is done writing. It also reduces the chances for filesystem corruption if the SD card is removed from the slot without unmounting it.

To improve write performance, the SD card may be mounted with the default async option instead. The performance cost of the sync mount option varies from card to card. Some cards will gain a 100% increase in throughput by using async instead of sync when mounting.

To use the async mount option (the default), modify the following line in /etc/fstab and remove “,sync”:
/dev/mmcblk0p1 /media/card auto defaults,sync 0 0

After modification, the line should read:
/dev/mmcblk0p1 /media/card auto defaults 0 0