xenserver5.6 报错: kernel: end_request: I/O error, dev sda, sector 4448230 解决方法。

xenserver 5.6 一直使用正常，一年来没有出过问题。可是最近老是报此错误。

而且报错硬盘上面的VPS都不正常，不能作任何后台操作。

end_request: I/O error, dev xvda, sector 1228741917
end_request: I/O error, dev xvda, sector 1228741917
end_request: I/O error, dev xvda, sector 1228741917
end_request: I/O error, dev xvda, sector 1228741917
end_request: I/O error, dev xvda, sector 1228741917
end_request: I/O error, dev xvda, sector 1228741917
end_request: I/O error, dev xvda, sector 1228741917
end_request: I/O error, dev xvda, sector 1228741917

Buffer I/O error on device dm-0, logical block 157360128
lost page write due to I/O error on dm-0
Buffer I/O error on device dm-0, logical block 157360129
lost page write due to I/O error on dm-0
Buffer I/O error on device dm-0, logical block 157360130
lost page write due to I/O error on dm-0
end_request: I/O error, dev xvda, sector 1247656509
Buffer I/O error on device dm-0, logical block 155930910
lost page write due to I/O error on dm-0
end_request: I/O error, dev xvda, sector 1247656517
Buffer I/O error on device dm-0, logical block 155930911
lost page write due to I/O error on dm-0
end_request: I/O error, dev xvda, sector 1899036597
Buffer I/O error on device dm-0, logical block 237353421

解决方法:

 第一种方法: a fix for this issue
http://support.citrix.com/article/CTX126365

第二种方法：
   直接升级系统到 xenserver 5.6 SP2版本。