Citrix 论坛上也提出了这个问题http://forums.citrix.com/thread.jspa?threadID=332289
我有一台 MD3200i，目前它与我的 Xen5.6 池配合得很好，但我无法连接到新的 6.2 池。我之前在 6.0 升级时遇到了问题（这就是旧池仍在 5.6 上的原因），但由于当时并不紧急，所以我回滚了它而不是修复它。
这次安装是在新机器上 - 我首先尝试了 6.1（有同样的问题）然后在安装后的第二天发布了 6.2，所以我切换到了它。
我有不是此时，我没有安装戴尔资源 DVD 上的任何东西 - 我找不到任何说我应该这样做的东西，而且我读过的所有内容都表明这不是必要的。
我可以从池中的两个服务器 ping 所有 8 个 IP 地址，iscsiadm -m discovery工作正常，我可以登录到节点并且 iscsiadm 报告会话正确处于活动状态。
我已将所需的部分添加到 multipath.conf，但 multipath -ll DM multipath kernel driver not loaded在启动后立即报告。
以下是启动后立即进行的测试会话的日志。
root@xen3 ~]# iscsiadm -m node --loginall=all
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.101,3260]
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.101,3260]
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.104,3260]
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.102,3260]
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.103,3260]
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.104,3260]
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.102,3260]
Logging in to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.103,3260]
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.101,3260]: successful
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.101,3260]: successful
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.104,3260]: successful
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.102,3260]: successful
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.103,3260]: successful
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.104,3260]: successful
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.130.102,3260]: successful
Login to [iface: default, target: iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91, portal: 192.168.131.103,3260]: successful
[root@xen3 ~]# iscsiadm -m session
tcp: [1] 192.168.130.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [2] 192.168.131.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [3] 192.168.131.104:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [4] 192.168.131.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [5] 192.168.130.103:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [6] 192.168.130.104:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [7] 192.168.130.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [8] 192.168.131.103:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
[root@xen3 ~]# service multipathd restart
ok
Stopping multipathd daemon: [ OK ]
Starting multipathd daemon: [ OK ]
[root@xen3 ~]# multipath
Jul 04 09:58:47 | DM multipath kernel driver not loaded
Jul 04 09:58:47 | DM multipath kernel driver not loaded
[root@xen3 ~]# multipath -ll
Jul 04 09:59:03 | DM multipath kernel driver not loaded
Jul 04 09:59:03 | DM multipath kernel driver not loaded
[
root@xen3 ~]# modprobe dm_multipath
[root@xen3 ~]# multipath
Jul 04 10:19:50 | 36b8ca3a0e7024800194a0bd11891cd14: ignoring map
create: 1Dell_Internal_Dual_SD_0123456789AB undef Dell,Internal Dual SD
size=1.9G features='0' hwhandler='0' wp=undef
`-+- policy='round-robin 0' prio=1 status=undef
`- 7:0:0:0 sdb 8:16 undef ready running
[root@xen3 ~]# multipath -ll
1Dell_Internal_Dual_SD_0123456789AB dm-1 Dell,Internal Dual SD
size=1.9G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=enabled
`- 7:0:0:0 sdb 8:16 active ready running
[root@xen3 ~]# iscsiadm -m session
tcp: [1] 192.168.130.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [2] 192.168.131.101:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [3] 192.168.131.104:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [4] 192.168.131.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [5] 192.168.130.103:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [6] 192.168.130.104:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [7] 192.168.130.102:3260,2 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
tcp: [8] 192.168.131.103:3260,1 iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
[root@xen3 ~]# dmesg | tail -n 50
[ 1161.881010] sd 8:0:0:0: [sdf] Unhandled error code
[ 1161.881013] sd 8:0:0:0: [sdf] Result: hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
[ 1161.881017] sd 8:0:0:0: [sdf] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[ 1161.881024] end_request: I/O error, dev sdf, sector 0
[ 1161.881031] Buffer I/O error on device sdf, logical block 0
[ 1161.881045] sd 15:0:0:0: [sdi] Unhandled error code
[ 1161.881048] sd 15:0:0:0: [sdi] Result: hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
[ 1161.881052] sd 15:0:0:0: [sdi] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[ 1161.881058] end_request: I/O error, dev sdi, sector 0
[ 1161.881065] Buffer I/O error on device sdi, logical block 0
[ 1161.881122] sd 9:0:0:0: [sdg] Unhandled error code
[ 1161.881124] sd 9:0:0:0: [sdg] Result: hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
[ 1161.881126] sd 9:0:0:0: [sdg] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[ 1161.881132] end_request: I/O error, dev sdg, sector 0
[ 1161.881140] Buffer I/O error on device sdg, logical block 0
[ 1168.220951] connection6:0: ping timeout of 15 secs expired, recv timeout 10, last rx 84060, last ping 85060, now 86560
[ 1168.220957] connection7:0: ping timeout of 15 secs expired, recv timeout 10, last rx 84060, last ping 85060, now 86560
[ 1168.220967] connection7:0: detected conn error (1011)
[ 1168.220969] connection4:0: ping timeout of 15 secs expired, recv timeout 10, last rx 84060, last ping 85060, now 86560
[ 1168.220973] connection4:0: detected conn error (1011)
[ 1168.220975] connection3:0: ping timeout of 15 secs expired, recv timeout 10, last rx 84060, last ping 85060, now 86560
[ 1168.220978] connection3:0: detected conn error (1011)
[ 1168.220985] connection6:0: detected conn error (1011)
[ 1168.480994] sd 14:0:0:0: [sde] Unhandled error code
[ 1168.480998] sd 14:0:0:0: [sde] Result: hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
[ 1168.481001] sd 14:0:0:0: [sde] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[ 1168.481009] end_request: I/O error, dev sde, sector 0
[ 1168.481015] Buffer I/O error on device sde, logical block 0
[ 1168.481076] sd 11:0:0:0: [sdc] Unhandled error code
[ 1168.481078] sd 11:0:0:0: [sdc] Result: hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
[ 1168.481080] sd 11:0:0:0: [sdc] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[ 1168.481087] end_request: I/O error, dev sdc, sector 0
[ 1168.481092] Buffer I/O error on device sdc, logical block 0
[ 1168.481144] sd 10:0:0:0: [sdd] Unhandled error code
[ 1168.481147] sd 10:0:0:0: [sdd] Result: hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
[ 1168.481150] sd 10:0:0:0: [sdd] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[ 1168.481156] end_request: I/O error, dev sdd, sector 0
[ 1168.481163] Buffer I/O error on device sdd, logical block 0
[ 1168.481168] sd 13:0:0:0: [sdj] Unhandled error code
[ 1168.481170] sd 13:0:0:0: [sdj] Result: hostbyte=DID_TRANSPORT_DISRUPTED driverbyte=DRIVER_OK
[ 1168.481172] sd 13:0:0:0: [sdj] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00
[ 1168.481178] end_request: I/O error, dev sdj, sector 0
[ 1168.481184] Buffer I/O error on device sdj, logical block 0
[ 1457.105996] device-mapper: multipath round-robin: version 1.0.0 loaded
[ 1457.106155] device-mapper: multipath: Cannot access device path 8:0: -16
[ 1457.106164] device-mapper: table: 252:1: multipath: error getting device
[ 1457.106172] device-mapper: ioctl: error adding target to table
[ 1457.171292] device-mapper: multipath: Cannot access device path 8:0: -16
[ 1457.171299] device-mapper: table: 252:1: multipath: error getting device
[ 1457.171304] device-mapper: ioctl: error adding target to table
[root@xen3 ~]# fdisk -l
Disk /dev/sda: 299.4 GB, 299439751168 bytes
255 heads, 63 sectors/track, 36404 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 1 5 40131 de Dell Utility
/dev/sda2 * 6 528 4194304 83 Linux
Partition 2 does not end on cylinder boundary.
/dev/sda3 528 1050 4194304 83 Linux
/dev/sda4 1050 36404 283986359+ 8e Linux LVM
Disk /dev/sdb: 2040 MB, 2040528896 bytes
255 heads, 63 sectors/track, 248 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 248 1992028+ 83 Linux
Disk /dev/dm-1: 2040 MB, 2040528896 bytes
255 heads, 63 sectors/track, 248 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/dm-1p1 1 248 1992028+ 83 Linux
[root@xen3 ~]# xe sr-probe type=lvmoiscsi device-config:target=192.168.130.101 device-config:targetIQN=iqn.1984-05.com.dell:powervault.md3200i.6782bcb0006bd850000000004ed88b91
Error code: SR_BACKEND_FAILURE_107
Error parameters: , The SCSIid parameter is missing or incorrect, <?xml version="1.0" ?>
<iscsi-target/>
笔记：xml 在最后一行正确结束 - 它永远不会返回 LUN 列表（并且这些服务器的 SAN 组中有一个 LUN 列表）。
答案1
查看其他地方的各种帖子，有人建议关闭交换机上的流量控制（线索显然是这些端口的以太网统计信息中显示的大量暂停数字），这没有帮助，但确实让我关注巨型帧支持。
ping 192.168.130.101 -s 6000 -M do（大数据包，不分段）无声无息地失败，而-s 9500 -M do报告了 ICMP 错误（正如我所料）。结合日志中的超时消息，这似乎是问题所在。
交换机设置似乎都很好，因此再次检查 XenCenter 配置时，我注意到 iSCSI 的 VLAN 网络的 MTU=9000，但底层 NIC 仍设置为 1500。显然，这不仅会弄乱巨型帧（这是合理的），而且不会产生 ICMP 错误（这对我来说似乎有点不对劲），因此一旦数据包通过 1500 并且没有收到任何错误或回复，流量就永远不会到达 SAN。
得到的经验教训是 - 确保顶级网络（我假设是相同的 VLAN 或绑定）的 MTU 始终不高于它们运行的网络。