我已将单个磁盘导出为targetcliLinux 主机上的 iSCSI 目标。在远程计算机上，我已连接到该设备，并在其上放置了一个 ZFS 卷（作为复制目标zrepl）。
但是，每次我重新启动 iSCSI 目标计算机时，运行 ZFS 的启动器计算机都会因写入错误而失败。经过一番研究，这种类型的故障仅发生在 ZFS 向设备发送写入时，它被告知写入已成功完成，但随后写入丢失。
这意味着 iSCSI 目标必须在实际写入磁盘之前缓存写入并返回成功，并且当机器重新启动时，这些缓存的写入并不总是被刷新。
有没有办法targetcli禁用此写入缓存，以便写入直到实际写入物理磁盘后才会返回成功？
我尝试将物理磁盘导出为pscsi后台存储，但这只会在访问磁盘时导致 iSCSI 目标内核崩溃。（没有使用虚拟机，只有两台本机 Linux 服务器，因此不应使用不常见的 SCSI 命令。）
/> ls
o- / .............................................................................................. [...]
o- backstores ................................................................................... [...]
| o- block ....................................................................... [Storage Objects: 1]
| | o- ar0 .......... [/dev/disk/by-id/ata-ST22000NT001-3LS101_ZX20XTYG (20.0TiB) write-thru activated]
| | o- alua ........................................................................ [ALUA Groups: 1]
| | o- default_tg_pt_gp ............................................ [ALUA state: Active/optimized]
| o- fileio ...................................................................... [Storage Objects: 0]
| o- pscsi ....................................................................... [Storage Objects: 0]
| o- ramdisk ..................................................................... [Storage Objects: 0]
o- iscsi ................................................................................. [Targets: 1]
| o- iqn.2023-07.com.example.host:sn.zx20xtyg ............................................... [TPGs: 1]
| o- tpg1 .................................................................... [no-gen-acls, no-auth]
| o- acls ............................................................................... [ACLs: 1]
| | o- iqn.2023-07.com.example.client:783af16f240 ................................ [Mapped LUNs: 1]
| | o- mapped_lun0 ........................................................ [lun0 block/ar0 (rw)]
| o- luns ............................................................................... [LUNs: 1]
| | o- lun0 ..... [block/ar0 (/dev/disk/by-id/ata-ST22000NT001-3LS101_ZX20XTYG) (default_tg_pt_gp)]
| o- portals ......................................................................... [Portals: 1]
| o- 0.0.0.0:3260 .......................................................................... [OK]
o- loopback .............................................................................. [Targets: 0]
o- vhost ................................................................................. [Targets: 0]
o- xen-pvscsi ............................................................................ [Targets: 0]
pool: iscsi
state: ONLINE
status: One or more devices are faulted in response to IO failures.
action: Make sure the affected devices are connected, then run 'zpool clear'.
see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-JQ
config:
NAME STATE READ WRITE CKSUM
iscsi ONLINE 0 0 0
wwn-0x60014050b85f5b1d12d4875bdb68f41a ONLINE 3 153 0
errors: List of errors unavailable: pool I/O is currently suspended
$ zpool clear iscsu
$ zpool status -v
pool: iscsi
state: ONLINE
status: One or more devices has experienced an error resulting in data
corruption. Applications may be affected.
action: Restore the file in question if possible. Otherwise restore the
entire pool from backup.
see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
scan: resilvered 360K in 00:00:02 with 0 errors on Fri Jul 28 12:58:10 2023
config:
NAME STATE READ WRITE CKSUM
iscsi ONLINE 0 0 0
wwn-0x60014050b85f5b1d12d4875bdb68f41a ONLINE 0 0 0
errors: Permanent errors have been detected in the following files:
<metadata>:<0x0>
<metadata>:<0x101>
<metadata>:<0x104>
<metadata>:<0x105>
<metadata>:<0x33>
<metadata>:<0x34>
<metadata>:<0x3d>
<metadata>:<0xe8d>
<metadata>:<0x1e1f9>
<metadata>:<0x1e1fb>
答案1
您需要使用 iSCSI 目标发送设置了 FUA（强制单元注意）标志的写入，或者在写入提交后发出“同步缓存”，然后再向调用者发送写入确认。如果您“映射”整个物理磁盘原始数据。