PowerPath：如何擴充 Linux 檔案系統，即使 PowerPath LUN 上沒有磁碟分割表格

Summary: PowerPath：如何擴充 Linux 檔案系統，即使 PowerPath LUN 上沒有磁碟分割表格。

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Symptoms

客戶嘗試在原生 Linux LVM 中對應的原生 Linux LVM 檔案系統 SAN LUN 中擴充兩個，但結果失敗。

執行 Linux 2.6.18-128.el5 的VNX5500透過 PowerPath 5.3 SP 1 （組建 111） 為 RHEL5 和 RHEL6 伺服器提供多個 LUN

客戶已在 VNX 上擴充這兩個 LUN 的使用者容量。
之前的容量為 82 GB 和 60 GB，後來分別擴充為 136 GB 和 90 GB。

客戶遵循的程序：

  1. lvdisplay -v /dev/[volgroup]/[logicalvolume] - 識別實體裝置
  2. fdisk -l /dev/[device] - 驗證分區表
  3. df -h /[mountpoint] - 驗證現有容量
  4. grep mpt /sys/class/scsi_host/host?/proc_name - 識別要重新掃描的SCSI總線
  5. echo "- - -" > /sys/class/scsi_host/hostX/scan - 重新掃描設備“hostX”
  6. pvs /dev/[device] - 檢查物理卷大小
  7. pvresize /dev/[device] - 將物理卷增加到新的 LUN 大小
  8. pvs /dev/[device] - 檢查新的物理卷大小
  9. vgscan - 重建卷組快取
  10. vgs [volgroup] - 驗證卷群組資訊
  11. lvextend -l +100%FREE /dev/[volgroup]/[logicalvolume] - 延伸邏輯卷以填滿磁碟
  12. resize2fs /dev/[volgroup]/[logicalvolume] - 調整邏輯卷上的檔案系統大小
  13. df -h /[mountpoint] - 驗證新容量

PowerPath 掛接的 LUN 似乎沒有有效的磁碟分割表格：

fdisk -l /dev/emcpowercb

Disk /dev/emcpowercb: 91.2 GB, 91268055040 bytes
255 heads, 63 sectors/track, 11096 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/emcpowercb doesn't contain a valid partition table

/dev/emcpowercb 的前 512 個字節如下：

 hexdump -Cn512 /dev/emcpowercb
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000200

然而，LUN 已掛接，可供系統存取 （例如）：

 df -h /DCCDBUNIX/data01
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg2dccdbnx2pd01-lvdccdbnxd01
84G 67G 13G 84% /DCCDBUNIX/data01

以上範例適用於下列 PowerPath 對應 LUN：

 vgdisplay -v vg2dccdbnx2pd01
Using volume group(s) on command line
Finding volume group "vg2dccdbnx2pd01"
--- Volume group ---
VG Name vg2dccdbnx2pd01

--- Logical volume ---
LV Name /dev/vg2dccdbnx2pd01/lvdccdbnxd01
VG Name vg2dccdbnx2pd01
LV Size 85.00 GB
Block device 253:9

--- Physical volumes ---
PV Name /dev/emcpowercb
Total PE / Free PE 21759 / 0

 

Cause

即使 PowerPath LUN 上沒有磁碟分割表格，仍嘗試擴充 Linux 檔案系統？

 

Resolution

根據 Red Hat 的說法，使用命令顯示實體磁碟區是正確的。

pvs -o+pv_used /dev/[pseudo_device]

然後在將磁碟新增至系統，並在新增磁碟上以等量擴充磁碟區群組時。

顯示原始 LUN 擴充時未使用的原始磁碟空間。

pvs -av /dev/[pseudo_device]

除了從主機掃描裝置之外，所有 PowerPath 原生裝置的 blockdev 命令也可依設計運作：

blockdev --rereadpt /dev/sds
blockdev --rereadpt /dev/sdbr
blockdev --rereadpt /dev/sddq

以下命令將萬用字元回應至 /sys/class/scsi_host/hostX/scan，因此使用主機重新掃描整個 HBA 以重新整理 LUN 裝置無法運作。

echo "1" >/sys/block/sds/device/rescan
echo "1" >/sys/block/sdbr/device/rescan
echo "1" >/sys/block/sddq/device/rescan

最後，在 Unisphere 中擴充 LUN 時，必須位於 root 中才能運作。

# powermt display dev=emcpowerai
Pseudo name=emcpowerai
VNX ID=APMXXXXXXXXXXX [xxxxx]
Logical device ID=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx [xxxxx_dccdbnx2i02_RV]
state=alive; policy=CLAROpt; queued-IOs=0
Owner: default=SP A, current=SP A Array failover mode: 4
==============================================================================
--------------- Host --------------- - Stor - -- I/O Path -- -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
3 lpfc sds SP A5 active alive 0 0
3 lpfc sdbr SP B5 active alive 0 0
4 lpfc sddq SP A4 active alive 0 0


 pvs -o+pv_used,dev_size |grep /dev/emcpowerai
/dev/emcpowerai vg2dccdbnx2qi01 lvm2 a-- 60.00G 0 60.00G 60.00G

 umount /DCCDBUNIX/index01

 blockdev --rereadpt /dev/sds
 blockdev --rereadpt /dev/sdbr
 blockdev --rereadpt /dev/sddq

 pvs -o+pv_used,dev_size |grep /dev/emcpowerai
/dev/emcpowerai vg2dccdbnx2qi01 lvm2 a-- 60.00G 0 60.00G 92.00G

 pvresize /dev/emcpowerai
Physical volume "/dev/emcpowerai" changed
1 physical volume(s) resized / 0 physical volume(s) not resized

 pvs -o+pv_used,dev_size |grep /dev/emcpowerai
/dev/emcpowerai vg2dccdbnx2qi01 lvm2 a-- 92.00G 32.00G 60.00G 92.00G

 pvscan |grep '/dev/emcpowerai'
PV /dev/emcpowerai VG vg2dccdbnx2qi01 lvm2 [92.00 GB / 32.00 GB free]

 vgscan |grep 'vg2dccdbnx2qi01'
Found volume group "vg2dccdbnx2qi01" using metadata type lvm2

 vgs |grep vg2dccdbnx2qi01
vg2dccdbnx2qi01 1 1 0 wz--n- 92.00G 32.00G

 lvextend -l +100%FREE /dev/vg2dccdbnx2qi01/lvdccdbnxi01

 lvextend -l +100%FREE /dev/vg2dccdbnx2qi01/lvdccdbnxi01
Extending logical volume lvdccdbnxi01 to 92.00 GB
Logical volume lvdccdbnxi01 successfully resized

 resize2fs /dev/vg2dccdbnx2qi01/lvdccdbnxi01
resize2fs 1.39 (29-May-2006)
Please run 'e2fsck -f /dev/vg2dccdbnx2qi01/lvdccdbnxi01' first.

e2fsck -f /dev/vg2dccdbnx2qi01/lvdccdbnxi01
e2fsck 1.39 (29-May-2006)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vg2dccdbnx2qi01/lvdccdbnxi01: 43/7864320 files (16.3% non-contiguous), 12034277/15727616 blocks

 resize2fs /dev/vg2dccdbnx2qi01/lvdccdbnxi01
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vg2dccdbnx2qi01/lvdccdbnxi01 to 24116224 (4k) blocks.
The filesystem on /dev/vg2dccdbnx2qi01/lvdccdbnxi01 is now 24116224 blocks long.

 mount /DCCDBUNIX/index01

 df -h
/dev/mapper/vg2dccdbnx2qi01-lvdccdbnxi01
91G 45G 41G 53% /DCCDBUNIX/index01

另一種選擇是重新啟動，這也有效，因為它會創建完全重新掃描。

 

Affected Products

PowerPath for Linux

Products

PowerPath for Linux
Article Properties
Article Number: 000064342
Article Type: Solution
Last Modified: 20 Oct 2025
Version:  5
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