Buffer I/O error on device sdb

Hi Gurus,

I'm running ver5.3.5 just previously upgrade, and this equipment just arrived for RMA 4 weeks ago. Somehow it works fine for the past weeks, and today it failed to process email, so after that i run tftpd to reload firmware, and few errors comming out.

So the questions is now, is this error from hardware or software? Please see below;

. Test Compact Flash and Harddisk. Testing write and read to hard disk(/dev/sda): Timing buffered disk reads: 64 MB in 0.60 seconds =106.25 MB/sec Timing buffered disk reads: 64 MB in 0.60 seconds =106.33 MB/sec Timing buffered disk reads: 64 MB in 0.60 seconds =106.74 MB/sec Average disk speed: 108996 KBPS vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv Read/write test PASS. Write/Read Rate: 22.66MBPS/ 249.24MBPS

Testing write and read to hard disk(/dev/sdb): Timing buffered disk reads: 64 MB in 5.07 seconds = 12.63 MB/sec Timing buffered disk reads: Buffer I/O error on device sdb, logical block 27712 Buffer I/O error on device sdb, logical block 27713 Buffer I/O error on device sdb, logical block 27714 Buffer I/O error on device sdb, logical block 27715 Buffer I/O error on device sdb, logical block 27716 Buffer I/O error on device sdb, logical block 27717 Buffer I/O error on device sdb, logical block 27718 Buffer I/O error on device sdb, logical block 27719 Buffer I/O error on device sdb, logical block 27720 Buffer I/O error on device sdb, logical block 27721 Buffer I/O error on device sdb, logical block 27744 Buffer I/O error on device sdb, logical block 27745 Buffer I/O error on device sdb, logical block 27746 Buffer I/O error on device sdb, logical block 27747 Buffer I/O error on device sdb, logical block 27748 Buffer I/O error on device sdb, logical block 27749 Buffer I/O error on device sdb, logical block 27750 Buffer I/O error on device sdb, logical block 27751 Buffer I/O error on device sdb, logical block 27752 Buffer I/O error on device sdb, logical block 27753 read() failed: No such file or directory Timing buffered disk reads: read() failed: Input/output error Average disk speed: 121926 KBPS v Read/write test PASS. Write/Read Rate: 3.15MBPS/ 11.96MBPS