{"id":7022,"date":"2019-04-10T14:46:29","date_gmt":"2019-04-10T11:46:29","guid":{"rendered":"http:\/\/unihost.com\/help\/?p=7022"},"modified":"2023-01-19T13:59:47","modified_gmt":"2023-01-19T10:59:47","slug":"how-to-restore-grub2","status":"publish","type":"post","link":"https:\/\/unihost.com\/help\/how-to-restore-grub2\/","title":{"rendered":"How to restore grub2"},"content":{"rendered":"
1) Boot a server in rescue mode
2) Check partitions
<\/em><\/span>
[root@rescue \/]# fdisk -l
<\/strong><\/span>
Disk \/dev\/sda: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors<\/span>
Units: sectors of 1 * 512 = 512 bytes<\/span>
Sector size (logical\/physical): 512 bytes \/ 512 bytes<\/span>
I\/O size (minimum\/optimal): 512 bytes \/ 512 bytes<\/span>
Disklabel type: gpt<\/span>
Disk identifier: 961524F0-9337-4FC8-B4AD-C65D8750BF58<\/span>
Device          Start        End    Sectors  Size Type<\/span>
\/dev\/sda1        2048    1048575    1046528  511M EFI System<\/span>
\/dev\/sda2     1048576 7812980735 7811932160  3.7T Linux RAID<\/span>
\/dev\/sda3  7812980736 7814027263    1046528  511M Linux swap<\/span>
Disk \/dev\/sdb: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors<\/span>
Units: sectors of 1 * 512 = 512 bytes<\/span>
Sector size (logical\/physical): 512 bytes \/ 512 bytes<\/span>
I\/O size (minimum\/optimal): 512 bytes \/ 512 bytes<\/span>
Disklabel type: gpt<\/span>
Disk identifier: 129DD84C-61D3-464B-910D-E87055EE5C4A<\/span>
Device          Start        End    Sectors  Size Type<\/span>
\/dev\/sdb1        2048    1048575    1046528  511M EFI System<\/span>
\/dev\/sdb2     1048576 7812980735 7811932160  3.7T Linux RAID<\/span>
\/dev\/sdb3  7812980736 7814027263    1046528  511M Linux swap<\/span>
Disk \/dev\/md2: 3.7 TiB, 3999709200384 bytes, 7811932032 sectors<\/span>
Units: sectors of 1 * 512 = 512 bytes<\/span>
Sector size (logical\/physical): 512 bytes \/ 512 bytes<\/span>
I\/O size (minimum\/optimal): 512 bytes \/ 512 bytes<\/span>



3) mount partitions<\/em><\/span>

<\/em><\/span>
root@rescue:~# mount \/dev\/md2 \/mnt\/<\/strong><\/span>
root@rescue:~# mount --bind \/dev\/ \/mnt\/dev<\/strong><\/span>
root@rescue:~# mount --bind \/sys \/mnt\/sys<\/strong><\/span>
root@rescue:~# mount --bind \/proc \/mnt\/proc<\/strong><\/span>
root@rescue:~# chroot \/mnt<\/strong><\/span>
[root@rescue \/]# mount \/dev\/sda1 \/mnt\/boot\/efi\/<\/strong><\/span>

<\/strong><\/span>
4) grub2 intallation<\/em><\/span>

<\/strong><\/span>
[root@rescue \/]# grub2-install --target=x86_64-efi --efi-directory=\/boot\/efi --bootloader-id=grub --recheck<\/strong><\/span>
Installing for x86_64-efi platform.<\/span>
Installation finished. No error reported.<\/span>


5) grub.cfg configuring <\/em><\/span>


[root@rescue \/]# grub2-mkconfig -o \/boot\/grub2\/grub.cfg<\/strong><\/span>
Generating grub configuration file ...<\/span>
Found linux image: \/boot\/bzImage-3.14.32-xxxx-grs-ipv6-64<\/span>
Found linux image: \/boot\/vmlinuz-3.10.0-693.5.2.el7.x86_64<\/span>
Found initrd image: \/boot\/initramfs-3.10.0-693.5.2.el7.x86_64.img<\/span>
Found linux image: \/boot\/vmlinuz-3.10.0-693.2.2.el7.x86_64<\/span>
Found initrd image: \/boot\/initramfs-3.10.0-693.2.2.el7.x86_64.img<\/span>
Found linux image: \/boot\/vmlinuz-0-rescue-1e98a4cc1263468b9f9a12e365316b95<\/span>
Found initrd image: \/boot\/initramfs-0-rescue-1e98a4cc1263468b9f9a12e365316b95.img<\/span>
Done<\/span>


6) exit and reboot<\/em><\/span>

ctrl+C
ctrl+D
root@rescue:~# reboot<\/strong><\/span><\/pre>\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
1) Boot a server in rescue mode2) Check partitions[root@rescue \/]# fdisk -lDisk \/dev\/sda: 3.7 TiB, 4000787030016 bytes, 7814037168 sectorsUnits: sectors of 1 * 512 = 512 bytesSector size (logical\/physical): 512 bytes \/ 512 bytesI\/O size (minimum\/optimal): 512 bytes \/ 512 bytesDisklabel type: gptDisk identifier: 961524F0-9337-4FC8-B4AD-C65D8750BF58Device          Start        End    Sectors  Size Type\/dev\/sda1        2048    1048575    1046528  511M EFI System\/dev\/sda2 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[158],"tags":[301,469,468],"class_list":["post-7022","post","type-post","status-publish","format-standard","hentry","category-dedicated-servers","tag-grub-bootloader","tag-grub2","tag-restore"],"yoast_head":"\nHow to restore grub2 - Unihost.FAQ<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/unihost.com\/help\/how-to-restore-grub2\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to restore grub2 - Unihost.FAQ\" \/>\n<meta property=\"og:description\" content=\"1) Boot a server in rescue mode2) Check partitions[root@rescue \/]# fdisk -lDisk \/dev\/sda: 3.7 TiB, 4000787030016 bytes, 7814037168 sectorsUnits: sectors of 1 * 512 = 512 bytesSector size (logical\/physical): 512 bytes \/ 512 bytesI\/O size (minimum\/optimal): 512 bytes \/ 512 bytesDisklabel type: gptDisk identifier: 961524F0-9337-4FC8-B4AD-C65D8750BF58Device          Start        End    Sectors  Size Type\/dev\/sda1        2048    1048575    1046528  511M EFI System\/dev\/sda2 […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/unihost.com\/help\/how-to-restore-grub2\/\" \/>\n<meta property=\"og:site_name\" content=\"Unihost.FAQ\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/unihost\/\" \/>\n<meta property=\"article:published_time\" content=\"2019-04-10T11:46:29+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2023-01-19T10:59:47+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/unihost.com\/help\/minio.php?.\/unihost-logo-alt.png\" \/>\n\t<meta property=\"og:image:width\" content=\"250\" \/>\n\t<meta property=\"og:image:height\" content=\"141\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"author\" content=\"Unihost Support\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@unihost\" \/>\n<meta name=\"twitter:site\" content=\"@unihost\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Unihost Support\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/unihost.com\/help\/how-to-restore-grub2\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/unihost.com\/help\/how-to-restore-grub2\/\"},\"author\":{\"name\":\"Unihost Support\",\"@id\":\"https:\/\/unihost.com\/help\/#\/schema\/person\/bb5ae95f38577c920e6a7507888b715a\"},\"headline\":\"How to restore grub2\",\"datePublished\":\"2019-04-10T11:46:29+00:00\",\"dateModified\":\"2023-01-19T10:59:47+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/unihost.com\/help\/how-to-restore-grub2\/\"},\"wordCount\":4,\"publisher\":{\"@id\":\"https:\/\/unihost.com\/help\/#organization\"},\"keywords\":[\"grub bootloader\",\"grub2\",\"restore\"],\"articleSection\":[\"02. 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