服务器救援模式下无法识别磁盘分区的数据恢复求助

我有一台带两块硬盘的服务器，现在处于救援模式——因为其中一块硬盘故障更换了，之后找了数据恢复服务，对方说数据已恢复但没法打开终端挂载文件系统，于是我通过SSH连接尝试挂载，但遇到了一堆问题。

我在救援模式下没法用fdisk命令，于是先试了lsblk，结果如下：

NAME  MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
loop0   7:0    0 190.9M  1 loop
sda     8:0    0 232.9G  0 disk
sdb     8:16   0 232.9G  0 disk

接着用parted -l查看分区，得到的错误是：

Error: /dev/sda: unrecognised disk label
Model: ATA Hitachi HDT72502 (scsi)
Disk /dev/sda: 250GB
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags:

Error: /dev/sdb: unrecognised disk label
Model: ATA Hitachi HDT72502 (scsi)
Disk /dev/sdb: 250GB
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags:

再试sgdisk -l /dev/sda，输出如下：

GPT fdisk (gdisk) version 1.0.6

Warning: Partition table header claims that the size of partition table entries is 257317316 bytes, but this program  supports only 128-byte entries.
Adjusting accordingly, but partition table may be garbage.
Warning: Partition table header claims that the size of partition table entries is 164259508 bytes, but this program  supports only 128-byte entries.
Adjusting accordingly, but partition table may be garbage.

Partition table scan:
MBR: not present
BSD: not present
APM: not present
GPT: not present

Creating new GPT entries in memory.
Disk /dev/sda: 488397168 sectors, 232.9 GiB
Model: Hitachi HDT72502
Sector size (logical/physical): 512/512 bytes Disk identifier (GUID): 6252014C-6128-5CBC-64B3-43B93D2746D4
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33 First usable sector is 34, last usable sector is 488397134 Partitions will be aligned on 2048-sector boundaries Total free space is 488397101 sectors (232.9 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name

对/dev/sdb执行同样命令sgdisk -l /dev/sdb，结果是：

GPT fdisk (gdisk) version 1.0.6

Warning: Partition table header claims that the size of partition table entries is 0 bytes, but this program  supports only 128-byte entries.
Adjusting accordingly, but partition table may be garbage.
Warning: Partition table header claims that the size of partition table entries is 0 bytes, but this program  supports only 128-byte entries.
Adjusting accordingly, but partition table may be garbage.

Partition table scan:
MBR: not present
BSD: not present
APM: not present
GPT: not present

Creating new GPT entries in memory.
Disk /dev/sdb: 488397168 sectors, 232.9 GiB
Model: Hitachi HDT72502
Sector size (logical/physical): 512/512 bytes Disk identifier (GUID): CBA264B1-5BCC-54F3-BF89-23B5C2B3733B
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33 First usable sector is 34, last usable sector is 488397134 Partitions will be aligned on 2048-sector boundaries Total free space is 488397101 sectors (232.9 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name

之后用dd if=/dev/sda|hexdump -C检查，发现/dev/sda确实有数据，但/dev/sdb是空的：

dd if=/dev/sdb|hexdump -C
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*

尝试用mdadm --query /dev/sda检查RAID信息，得到：

/dev/sda: is not an md array

另外，我只能通过远程SSH连接，且可用命令只有这些：

agetty            devlink          e2undo       fsck.reiserfs  ip           lvconvert    lvscan       mkfs.msdos         pvchange         route              sysctl           vgextend
badblocks         dhcpcd           ethtool      fsck.vfat      ipmaddr      lvcreate     mdadm        mkfs.reiserfs      pvck             rtacct             tc               vgimport
blkdeactivate     dmeventd         fatlabel     fsck.xfs       iptunnel     lvdisplay    mdmon        mkfs.vfat          pvcreate         rtmon              telinit          vgimportclone
blkdiscard        dmraid           findfs       fsfreeze       isosize      lvextend     mii-tool     mkfs.xfs           pvdisplay        runlevel           tipc             vgmerge
blkid             dmraid-activate  fixparts     fstab-decode   jfs_debugfs  lvm          mkdosfs      mkhomedir_helper   pvmove           runuser            tune2fs          vgmknodes
blkzone           dmsetup          fsadm        fstrim         jfs_fsck     lvmconfig    mke2fs       mkreiserfs         pvremove         setcap             tunefs.reiserfs  vgreduce
blockdev          dmstats          fsck         gdisk          jfs_fscklog  lvmdiskscan  mkfs         mkswap             pvresize         sgdisk             unix_chkpwd      vgremove
bridge            dosfsck          fsck.btrfs   getcap         jfs_logdump  lvmdump      mkfs.bfs     nameif             pvs              shadowconfig       unix_update      vgrename
capsh             dosfslabel       fsck.cramfs  getpcaps       jfs_mkfs     lvmpolld     mkfs.btrfs   parted             pvscan           shutdown           vgcfgbackup      vgs
cgdisk            dumpe2fs         fsck.ext2    getty          jfs_tune     lvmsadc      mkfs.cramfs  partprobe          rarp             slattach           vgcfgrestore     vgscan
chcpu             e2fsck           fsck.ext3    halt           killall5     lvmsar       mkfs.ext2    pivot_root         raw              start-stop-daemon  vgchange         vgsplit
coldreboot        e2image          fsck.ext4    hdparm         kpartx       lvreduce     mkfs.ext3    plipconfig         reboot           sulogin            vgck             wipefs
ctrlaltdel        e2label          fsck.fat     hwclock        ldconfig     lvremove     mkfs.ext4    pm-hibernate       reiserfsck       swaplabel          vgconvert        xfs_repair
debugfs           e2mmpstatus      fsck.jfs     ifconfig       logsave      lvrename     mkfs.fat     pm-suspend         reiserfstune     swapoff            vgcreate         zramctl
debugfs.reiserfs  e2scrub          fsck.minix   init           losetup      lvresize     mkfs.jfs     pm-suspend-hybrid  resize2fs        swapon             vgdisplay
debugreiserfs     e2scrub_all      fsck.msdos   installkernel  lvchange     lvs          mkfs.minix   poweroff           resize_reiserfs  switch_root        vgexport

我该怎么恢复分区呢？我觉得可能没希望了，但还是想试试，因为数据恢复服务说数据还能救。

任何建议都非常感谢，提前谢谢大家！

备注：内容来源于stack exchange，提问作者EDP