Repeated corruption running linux on USB flash drive

I have a HP Proliant N40L server and in the internal USB socket I have a 16GB HP v195b flash drive on which I have a full copy of Debian installed from a copy of the DVD1 ISO image.

In as far as installation and operation goes my setup works okay, but I keep experiencing corruption of the file system on the flash drive. Originally I used a 4GB flash drive (same brand and model but bought from a different supplier) but needed more space so upgraded. Both drives have experience this problem with corruption, so I can rule out it being just a unlucky experience with bad flash drive.

In order to reduce writing to the flash drive I have it formatted in Ext2, and mount bind various directories to a hard disk. This allows me to have a standard setup, but if the hard disk fails or is not present it can in an emergency run solely from the flash drive. From my fstab file those binds are:

/mnt/internal/os/home                     /home               bind    defaults,bind                      0       0
/mnt/internal/os/etc/network/run          /etc/network/run    bind    defaults,bind                      0       0
/mnt/internal/os/tmp                      /tmp                bind    defaults,bind                      0       0
/mnt/internal/os/var/tmp                  /var/tmp            bind    defaults,bind                      0       0
/mnt/internal/os/var/cache                /var/cache          bind    defaults,bind                      0       0
/mnt/internal/os/var/lib                  /var/lib            bind    defaults,bind                      0       0
/mnt/internal/os/var/log                  /var/log            bind    defaults,bind                      0       0
/mnt/internal/os/var/lock                 /var/lock           bind    defaults,bind                      0       0
/mnt/internal/os/var/mail                 /var/mail           bind    defaults,bind                      0       0
/mnt/internal/os/var/run                  /var/run            bind    defaults,bind                      0       0
/mnt/internal/os/var/spool                /var/spool          bind    defaults,bind                      0       0
/mnt/internal/os/var/swap                 /var/swap           bind    defaults,bind                      0       0

Recently the corruption became so bad to be unusable so I rebuilt the server from scratch. As part of this I did a full read and write surface scan of the USB which did not find any hardware faults. Since then the server had been left running constantly yet the corruption has reoccurred.

Has anyone experienced anything like this? Searching the web has not given me any similar examples, nor have I been able to find anyone having a problem with the v195b flash drives.

Are there other obvious directories I should relocate to the hard drive. I realize doing this there will come a point when running from the USB becomes pointless, but I want the flexibility to be able to swap disks easily. Or at least I will do once prices drop to their original levels.

Is there anything obvious I am missing that could be the cause? As it does not seem to be a hardware fault, nor a loss of power while writing, I cannot see any reason why this should be happening. I do wonder if enabling journaling would resolve the problems, but that would not be ideal for a flash drive.

Any help or advice would be greatly appreciated.