1. はじめに
sdp profileがサポートされることにより、250GB以上のboot diskもサポートされるようになりました。 試しに1500GBで注文したサーバーが以下の通り。
- 注文時のBoot Volumeの構成(1500GB)
でも、、、
- あれ、1500GBはどこに行った？
- Cドライブは100GBしか認識していない。その後ろは割り当てされていない領域や、Dドライブやリカバリー領域など、混在している。
Cドライブを拡張しようとしても、後ろにDドライブやリカバリー領域があるため、Windowsの標準機能ではそのままでは拡張できません（3rd Partyツールであればサポートしているものもあるようです）。正直綺麗とは言い難い構成です。なお、DドライブはUEFIブートのための領域のようです。単体のイメージでBIOS/MBRとUEFI/GPTをサポートするためにこういう構成になっているのでしょう。
なんじゃこりゃ！？って思ったら、以下のようなdocsの記述と手順がありました。どうやらDドライブやRecovery領域は削除し、Cドライブを拡張した後に、再度Recovery領域を作成すれば良いようです。しかし、このdocsの通りやってもRecovery領域を回復できないので、事前にRecovery領域をコピーしておくといったアレンジをしてみました。
https://cloud.ibm.com/docs/vpc?topic=vpc-troubleshooting-unexpandable-c-drive
方針は以下の通りです。
- Dドライブを削除（sdp profileを使っている場合、本稿執筆時点ではBIOS/MBRで起動してきている。少なくとも2TB以内であればUEFI/GPTにする必要はない。将来的にsecure bootなどがサポートされるようになったらまた再考が必要だが、少なくとも本稿執筆時点ではsdp profileではsecure bootはサポートされていない。）
- Recovery Partitionをバックアップをしておき、Cドライブを広げた後に、再構築
2. 拡張手順
Recovery領域の確認
PS C:\> reagentc /info
Windows Recovery Environment (Windows RE) and system reset configuration
Information:
Windows RE status: Enabled
Windows RE location: \\?\GLOBALROOT\device\harddisk0\partition4\Recovery\WindowsRE
Boot Configuration Data (BCD) identifier: 31a07952-4143-11f0-9c1d-0800277b2ea2
Recovery image location:
Recovery image index: 0
Custom image location:
Custom image index: 0
REAGENTC.EXE: Operation Successful.s
DISK構成の確認
PS C:\> Get-Disk | sort Number | ft -Auto
Number Friendly Name Serial Number HealthStatus OperationalStatus Total Size Partition Style
------ ------------- ------------- ------------ ----------------- ---------- ---------------
0 Red Hat VirtIO 02e7-32b820fe-8db2-4 Healthy Online 1.46 TB MBR
1 Red Hat VirtIO cloud-init- Healthy Online 44 KB RAW
2 QEMU QEMU HARDDISK cloud-init-02e7_5058d21c-c282-4b80-9 Healthy Online 380 KB RAW
PS C:\> diskpart
Microsoft DiskPart version 10.0.26100.1150
Copyright (C) Microsoft Corporation.
On computer: SYASUDA-WIN25
DISKPART> list disk
Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
Disk 0 Online 1500 GB 0 B
Disk 1 Online 44 KB 44 KB
Disk 2 Online 380 KB 380 KB
DISKPART> select disk 0
Disk 0 is now the selected disk.
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 NTFS Partition 100 MB Healthy System
Volume 1 C NTFS Partition 98 GB Healthy Boot
Volume 2 D FAT32 Partition 200 MB Healthy
Volume 3 Windows RE NTFS Partition 887 MB Healthy Hidden
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Primary 100 MB 1024 KB
Partition 2 Primary 98 GB 101 MB
Partition 3 Primary 200 MB 98 GB
Partition 4 Recovery 887 MB 99 GB
Recovery領域にDrive Letter Rを割り当てる
DISKPART> select partition 4
Partition 4 is now the selected partition.
DISKPART> assign Letter=R
DiskPart successfully assigned the drive letter or mount point.
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 NTFS Partition 100 MB Healthy System
Volume 1 C NTFS Partition 98 GB Healthy Boot
Volume 2 D FAT32 Partition 200 MB Healthy
* Volume 3 R Windows RE NTFS Partition 887 MB Healthy Hidden
DISKPART> exit
リカバリー領域のコピー
PS C:\> mkdir C:\backup
Directory: C:\
Mode LastWriteTime Length Name
---- ------------- ------ ----
d----- 6/5/2026 4:03 AM backup
PS C:\> mkdir C:\backup\WindowsRE
Directory: C:\backup
Mode LastWriteTime Length Name
---- ------------- ------ ----
d----- 6/5/2026 4:03 AM WindowsRE
PS C:\> robocopy R:\Recovery\WindowsRE C:\backup\WindowsRE /E /COPYALL /R:1 /W:1
-------------------------------------------------------------------------------
ROBOCOPY :: Robust File Copy for Windows
-------------------------------------------------------------------------------
Started : Friday, June 5, 2026 4:04:04 AM
Source : R:\Recovery\WindowsRE\
Dest : C:\backup\WindowsRE\
Files : *.*
Options : *.* /S /E /COPYALL /R:1 /W:1
------------------------------------------------------------------------------
4 R:\Recovery\WindowsRE\
100% New File 3.0 m boot.sdi
100% New File 1155 ReAgent.xml
New File 0 SrSettings.ini
100% New File 659.5 m winre.wim
------------------------------------------------------------------------------
Total Copied Skipped Mismatch FAILED Extras
Dirs : 1 0 1 0 0 0
Files : 4 4 0 0 0 0
Bytes : 662.56 m 662.56 m 0 0 0 0
Times : 0:00:09 0:00:09 0:00:00 0:00:00
Speed : 73,386,382 Bytes/sec.
Speed : 4,199.203 MegaBytes/min.
Ended : Friday, June 5, 2026 4:04:14 AM
PS C:\> dir C:\backup\WindowsRE -Force
Directory: C:\backup\WindowsRE
Mode LastWriteTime Length Name
---- ------------- ------ ----
---hs- 4/1/2024 2:00 AM 3170304 boot.sdi
---hs- 6/5/2026 3:34 AM 1155 ReAgent.xml
---hs- 10/14/2025 11:11 PM 0 SrSettings.ini
---hs- 5/15/2026 6:25 AM 691577427 winre.wim
Recovery 領域の無効化
PS C:\> reagentc /disable
REAGENTC.EXE: Operation Successful.
PS C:\> reagentc /info
Windows Recovery Environment (Windows RE) and system reset configuration
Information:
Windows RE status: Disabled
Windows RE location:
Boot Configuration Data (BCD) identifier: 00000000-0000-0000-0000-000000000000
Recovery image location:
Recovery image index: 0
Custom image location:
Custom image index: 0
REAGENTC.EXE: Operation Successful.
PS C:\> reagentc /info
Windows Recovery Environment (Windows RE) and system reset configuration
Information:
Windows RE status: Enabled
Windows RE location: \\?\GLOBALROOT\device\harddisk0\partition4\Recovery\WindowsRE
Boot Configuration Data (BCD) identifier: 31a07952-4143-11f0-9c1d-0800277b2ea2
Recovery image location:
Recovery image index: 0
Custom image location:
Custom image index: 0
REAGENTC.EXE: Operation Successful.
パーティション4（リカバリー領域の削除）
PS C:\> diskpart
Microsoft DiskPart version 10.0.26100.1150
Copyright (C) Microsoft Corporation.
On computer: SYASUDA-WIN25
DISKPART> select disk 0
Disk 0 is now the selected disk.
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Primary 100 MB 1024 KB
Partition 2 Primary 98 GB 101 MB
Partition 3 Primary 200 MB 98 GB
Partition 4 Recovery 887 MB 99 GB
DISKPART> select partition 4
Partition 4 is now the selected partition.
DISKPART> delete partition override
DiskPart successfully deleted the selected partition.
パーティション3（Dドライブ）の削除
DISKPART> select partition 3
Partition 3 is now the selected partition.
DISKPART> delete partition override
DiskPart successfully deleted the selected partition.
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Primary 100 MB 1024 KB
Partition 2 Primary 98 GB 101 MB
Cドライブ（パーティション2）の拡張
DISKPART> select partition 2
Partition 2 is now the selected partition.
DISKPART> extend
DiskPart successfully extended the volume.
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Primary 100 MB 1024 KB
* Partition 2 Primary 1499 GB 101 MB
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 NTFS Partition 100 MB Healthy System
* Volume 1 C NTFS Partition 1499 GB Healthy Boot
Cドライブから1000MB割り当ててRecovery領域を作成
DISKPART> shrink minimum=1000
DiskPart successfully shrunk the volume by: 1000 MB
DISKPART> create partition primary
DiskPart succeeded in creating the specified partition.
DISKPART> format quick fs=ntfs label=Recovery
100 percent completed
DiskPart successfully formatted the volume.
DISKPART> set id=27
DiskPart successfully set the partition ID.
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Primary 100 MB 1024 KB
Partition 2 Primary 1498 GB 101 MB
* Partition 3 Recovery 1000 MB 1499 GB
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 NTFS Partition 100 MB Healthy System
Volume 1 C NTFS Partition 1498 GB Healthy Boot
* Volume 2 Recovery NTFS Partition 1000 MB Healthy Hidden
Drive Letter Rを割り当ててリストアを実施
DISKPART> assign letter=R
DiskPart successfully assigned the drive letter or mount point.
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 NTFS Partition 100 MB Healthy System
Volume 1 C NTFS Partition 1498 GB Healthy Boot
* Volume 2 R Recovery NTFS Partition 1000 MB Healthy Hidden
DISKPART> exit
PS C:\> robocopy C:\backup\WindowsRE R:\Recovery\WindowsRE /E /COPYALL /R:1 /W:1
-------------------------------------------------------------------------------
ROBOCOPY :: Robust File Copy for Windows
-------------------------------------------------------------------------------
Started : Friday, June 5, 2026 4:17:01 AM
Source : C:\backup\WindowsRE\
Dest : R:\Recovery\WindowsRE\
Files : *.*
Options : *.* /S /E /COPYALL /R:1 /W:1
------------------------------------------------------------------------------
New Dir 4 C:\backup\WindowsRE\
100% New File 3.0 m boot.sdi
100% New File 1155 ReAgent.xml
New File 0 SrSettings.ini
100% New File 659.5 m winre.wim
------------------------------------------------------------------------------
Total Copied Skipped Mismatch FAILED Extras
Dirs : 1 1 0 0 0 0
Files : 4 4 0 0 0 0
Bytes : 662.56 m 662.56 m 0 0 0 0
Times : 0:00:10 0:00:10 0:00:00 0:00:00
Speed : 69,363,906 Bytes/sec.
Speed : 3,969.035 MegaBytes/min.
Ended : Friday, June 5, 2026 4:17:11 AM
PS C:\> dir R:\Recovery\WindowsRE -force
Directory: R:\Recovery\WindowsRE
Mode LastWriteTime Length Name
---- ------------- ------ ----
---hs- 4/1/2024 2:00 AM 3170304 boot.sdi
---hs- 6/5/2026 3:34 AM 1155 ReAgent.xml
---hs- 10/14/2025 11:11 PM 0 SrSettings.ini
---hs- 5/15/2026 6:25 AM 691577427 winre.wim
PS C:\> reagentc /setreimage /path R:\Recovery\WindowsRE
Directory set to: \\?\GLOBALROOT\device\harddisk0\partition3\Recovery\WindowsRE
REAGENTC.EXE: Operation Successful.
PS C:\> reagentc /enable
REAGENTC.EXE: Operation Successful.
PS C:\> reagentc /info
Windows Recovery Environment (Windows RE) and system reset configuration
Information:
Windows RE status: Enabled
Windows RE location: \\?\GLOBALROOT\device\harddisk0\partition3\Recovery\WindowsRE
Boot Configuration Data (BCD) identifier: 31a07954-4143-11f0-9c1d-0800277b2ea2
Recovery image location:
Recovery image index: 0
Custom image location:
Custom image index: 0
REAGENTC.EXE: Operation Successful.
Dirve Letterを削除
PS C:\> diskpart
Microsoft DiskPart version 10.0.26100.1150
Copyright (C) Microsoft Corporation.
On computer: SYASUDA-WIN25
DISKPART> list disk
Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
Disk 0 Online 1500 GB 0 B
Disk 1 Online 44 KB 44 KB
Disk 2 Online 380 KB 380 KB
DISKPART> select disk 0
Disk 0 is now the selected disk.
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 NTFS Partition 100 MB Healthy System
Volume 1 C NTFS Partition 1498 GB Healthy Boot
Volume 2 R Recovery NTFS Partition 1000 MB Healthy Hidden
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Primary 100 MB 1024 KB
Partition 2 Primary 1498 GB 101 MB
Partition 3 Recovery 1000 MB 1499 GB
DISKPART> select partition 3
Partition 3 is now the selected partition.
DISKPART> remove letter=R
DiskPart successfully removed the drive letter or mount point.
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 NTFS Partition 100 MB Healthy System
Volume 1 C NTFS Partition 1498 GB Healthy Boot
* Volume 2 Recovery NTFS Partition 1000 MB Healthy Hidden
DISKPART> exit
Leaving DiskPart...
3. 最終完成系
Cドライブが拡張され、その一番最後にRecovery領域が作成されている。
4. Recovery領域の動作確認
次回起動時にRecovery領域を使ってBoot
PS C:\> reagentc /boottore
REAGENTC.EXE: Operation Successful.
再起動
PS C:\> shudown /r /t 0
VNCコンソールでRecoveryモードになっていることを確認
