Monthly Archives: August 2019

Installing Red Hat Linux in a M.2 that crashes the installer

Few months ago I encountered with a problem with RHEL installer and some of the M.2 drives.

I’ve productized my Product, to be released with M.2 booting SATA drives of 128GB.

The procedure for preparing the Servers (90 and 60 drives, Cold Storage) was based on the installation of RHEL in the M.2 128GB drive. Then the drives are cloned.

Few days before mass delivery the company request to change the booting M.2 drives for others of our own, 512 GB drives.

I’ve tested many different M.2 drives and all of them were slightly different.

Those 512 GB M.2 drives had one problem… Red Hat installer was failing with a python error.

We were running out of time, so I decided to clone directly from the 128GB M.2 working card, with everything installed, to the 512 GB card. Doing that is so easy as booting with a Rescue Linux USB disk, and then doing a dd from the 128GB drive to the 512GB drive.

Booting with a live USB system is important, as Filesystem should not be mounted to prevent corruption when cloning.

Then, the next operation would be booting the 512 GB drive and instructing Linux to claim the additional space.

Here is the procedure for doing it (note, the OS installed in the M.2 was CentOS in this case):

Determine the device that needs to be operated on (this will usually be the boot drive); in this example it is /dev/sdae

# df -h 
Filesystem                             Size  Used Avail Use% Mounted on
/dev/mapper/centos_4602c-root           50G  2.4G   47G   1% /
devtmpfs                                16G     0   16G   0% /dev
tmpfs                                   16G     0   16G   0% /dev/shm
tmpfs                                   16G  395M   16G   3% /run
tmpfs                                   16G     0   16G   0% /sys/fs/cgroup
/dev/sdae1                            1014M  146M  869M  15% /boot
/dev/mapper/centos_4602c-home           57G   33M   57G   1% /home
tmpfs                                  3.2G     0  3.2G   0% /run/user/0
logs                                    68G  7.4M   68G   1% /logs
mysql                                  481G  128K  481G   1% /mysql
N58-C3-D16-P3-S1                       491T  334G  490T   1% /N58-C3-D16-P3-S1

Extend the OS partition using Parted

# parted /dev/sdae
print
resizepart PART_NUMBER END
quit

Where:

  • PART_NUMBER: Is the partition number obtained from the “print” command
  • END: This is the end of the drive; for example, for a 50GB drive, enter 50000

Examining the LVM Partitions

The centos_4602c-root LVM partition is the one we want to extend.

# lsblk /dev/sdae
NAME                          MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sdae                           65:224  0   477G  0 disk 
├─sdae1                        65:225  0     1G  0 part /boot
└─sdae2                        65:226  0 475.9G  0 part 
  ├─centos_4602c-root         253:0    0    50G  0 lvm  /
  ├─centos_4602c-swap         253:1    0  11.9G  0 lvm  [SWAP]
  └─centos_4602c-home         253:2    0  56.3G  0 lvm  /home

Using LVM Commands

The following commands will:

  • Display the LVM volumes on the system
  • Resize a volume (device)
  • Re-display the updated LVM volumes
  • Extend the desired LVM partition (lvextend command)
# pvdisplay
  /dev/sdbm: open failed: No medium found
  /dev/sdbn: open failed: No medium found
  /dev/sdbj: open failed: No medium found
  /dev/sdbk: open failed: No medium found
  /dev/sdbl: open failed: No medium found
  --- Physical volume ---
  PV Name               /dev/sdae2
  VG Name               centos_4602c
  PV Size               118.24 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              30269
  Free PE               0
  Allocated PE          30269
  PV UUID               yvHO6t-cYHM-CCCm-2hOO-mJWf-6NUI-zgxzwc
# pvresize /dev/sdae2
  /dev/sdbm: open failed: No medium found
  /dev/sdbn: open failed: No medium found
  /dev/sdbj: open failed: No medium found
  /dev/sdbk: open failed: No medium found
  /dev/sdbl: open failed: No medium found
  Physical volume "/dev/sdae2" changed
  1 physical volume(s) resized or updated / 0 physical volume(s) not resized
# pvdisplay
  /dev/sdbm: open failed: No medium found
  /dev/sdbn: open failed: No medium found
  /dev/sdbj: open failed: No medium found
  /dev/sdbk: open failed: No medium found
  /dev/sdbl: open failed: No medium found
  --- Physical volume ---
  PV Name               /dev/sdae2
  VG Name               centos_4602c
  PV Size               <475.84 GiB / not usable 3.25 MiB
  Allocatable           yes 
  PE Size               4.00 MiB
  Total PE              121813
  Free PE               91544
  Allocated PE          30269
  PV UUID               yvHO6t-cYHM-CCCm-2hOO-mJWf-6NUI-zgxzwc
# vgdisplay
  --- Volume group ---
  VG Name               centos_4602c
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               <475.93 GiB
  PE Size               4.00 MiB
  Total PE              121838
  Alloc PE / Size       30269 / <118.24 GiB
  Free  PE / Size       91569 / 357.69 GiB
  VG UUID               ORcp2t-ntwQ-CNSX-NeXL-Udd9-htt9-kLfvRc
# lvextend -l +91569 /dev/centos_4602c/root 
  Size of logical volume centos_4602c/root changed from 50.00 GiB (12800 extents) to <407.69 GiB (104369 extents).
  Logical volume centos_4602c/root successfully resized.

Extend the xfs file system to use the extended space

The xfs file system for the root partition will need to be extended to use the extra space; this is done using the xfs_grow command as shown below.

# xfs_growfs /dev/centos_4602c/root  
meta-data=/dev/mapper/centos_4602c-root isize=512    agcount=4, agsize=3276800 blks
         =                       sectsz=512   attr=2, projid32bit=1          =                       crc=1        finobt=0 spinodes=0 data     =                       bsize=4096   blocks=13107200, imaxpct=25 
         =                       sunit=0      swidth=0 blks 
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1 log      =internal               bsize=4096   blocks=6400, version=2          =                       sectsz=512   sunit=0 blks, lazy-count=1 
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 13107200 to 106873856 

Verify the results

Note that the c-root LVM partition is now 408GB.

# df -h 
Filesystem                             Size  Used Avail Use% Mounted on
/dev/mapper/centos_4602c-root          408G  2.4G  406G   1% /
devtmpfs                                16G     0   16G   0% /dev
tmpfs                                   16G     0   16G   0% /dev/shm
tmpfs                                   16G  395M   16G   3% /run
tmpfs                                   16G     0   16G   0% /sys/fs/cgroup
/dev/sdae1                            1014M  146M  869M  15% /boot
/dev/mapper/centos_4602c-home           57G   33M   57G   1% /home
tmpfs                                  3.2G     0  3.2G   0% /run/user/0
logs                                    68G  7.4M   68G   1% /logs
mysql                                  481G  128K  481G   1% /mysql
N58-C3-D16-P3-S1                       491T  334G  490T   1% /N58-C3-D16-P3-S1

So now we are able to clone directly from one 512GB to another.

You may be interested to take a look to the commands:

growpart
resize2fs
xfs_growfs (from xfsprogs package)

If you want to do this in an instance in Amazon, here is a very good documentation.

A sample forensic post mortem for a iSCSI Initiator (client) that had connectivity problems to the Server

My Team in The States report an issue with a Red Hat iSCSI Initiator having issues connecting to a Volume exported by a ZFS Server.

There is an issue on GitLab.

As I always do when I troubleshot a problem, I create a forensics post-mortem document recording everything I do, so later, others can learn how I fix it, or they can learn the steps I did in order to troubleshoot.

Please note: Some Ip addresses have been manually edited.

2019-08-09 10:20:10 Start of the investigation

I log into the Server, with Ip Address: xxx.yyy.16.30. Is an All-Flash-Array Server with RHEL6.10 and DRAID v.08091350.

Htop shows normal/low activity.

I check the addresses in the iSCSI Initiator (client), to make sure it is connecting to the right Server.

[root@Host-164 ~]# ip addr list 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
    valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether 00:25:90:c5:1e:ea brd ff:ff:ff:ff:ff:ff
    inet xxx.yyy.13.164/16 brd xxx.yyy.255.255 scope global eno1
    valid_lft forever preferred_lft forever
    inet6 fe80::225:90ff:fec5:1eea/64 scope link
    valid_lft forever preferred_lft forever
3: eno2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN qlen 1000
    link/ether 00:25:90:c5:1e:eb brd ff:ff:ff:ff:ff:ff 
4: enp3s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether 24:8a:07:a4:94:9c brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.164/24 brd 192.168.100.255 scope global enp3s0f0
    valid_lft forever preferred_lft forever
    inet6 fe80::268a:7ff:fea4:949c/64 scope link
    valid_lft forever preferred_lft forever 
5: enp3s0f1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether 24:8a:07:a4:94:9d brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.164/24 brd 192.168.200.255 scope global enp3s0f1
    valid_lft forever preferred_lft forever inet6 fe80::268a:7ff:fea4:949d/64 scope link
    valid_lft forever preferred_lft forever                                                                                                       
                                                                                                                                

I see the luns on the host, connecting to the 10Gbps of the Server:

[root@Host-164 ~]# iscsiadm -m session
 tcp: [10] 192.168.100.30:3260,1 iqn.2003-01.org.linux-iscsi:vol4 (non-flash)
 tcp: [11] 192.168.100.30:3260,1 iqn.2003-01.org.linux-iscsi:vol5 (non-flash)
 tcp: [7] 192.168.100.30:3260,1 iqn.2003-01.org.linux-iscsi:vol1 (non-flash)
 tcp: [8] 192.168.100.30:3260,1 iqn.2003-01.org.linux-iscsi:vol2 (non-flash)
 tcp: [9] 192.168.100.30:3260,1 iqn.2003-01.org.linux-iscsi:vol3 (non-flash)

Finding the misteries…

Executing cat /proc/partitions is a bit strange respect mount:

[root@Host-164 ~]# cat /proc/partitions
 major minor #blocks name
 8  0 125034840 sda
 8  1 512000 sda1
 8  2 124521472 sda2
 253 0 12505088 dm-0
 253 1 112013312 dm-1
 8 32 104857600 sdc
 8 16 104857600 sdb
 8 48 104857600 sdd
 8 64 104857600 sde
 8 80 104857600 sdf

As mount has this:

/dev/sdg1 on /mnt/large type ext4 (ro,relatime,seclabel,data=ordered)

Lsblk shows that /dev/sdg is not present:

[root@Host-164 ~]# lsblk
 NAME
 MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
 sda 8:0 0 119.2G 0 disk
 ├─sda1 8:1 0 500M 0 part /boot
 └─sda2 8:2 0 118.8G 0 part
  ├─rhel-swap 253:0 0 11.9G 0 lvm [SWAP]
  └─rhel-root 253:1 0 106.8G 0 lvm /
 sdb 8:16 0 100G 0 disk
 sdc 8:32 0 100G 0 disk
 sdd 8:48 0 100G 0 disk
 sde 8:64 0 100G 0 disk
 sdf 8:80 0 100G 0 disk

And as expected:

[root@Host-164 ~]# ls -al /mnt/large
 ls: reading directory /mnt/large: Input/output error
 total 0

I see that the Volumes appear to not having being partitioned:

[root@Host-164 ~]# fdisk /dev/sdf
 Welcome to fdisk (util-linux 2.23.2).
 Changes will remain in memory only, until you decide to write them.
 Be careful before using the write command.
 Device does not contain a recognized partition table
 Building a new DOS disklabel with disk identifier 0xddf99f40.
 Command (m for help): p
 Disk /dev/sdf: 107.4 GB, 107374182400 bytes, 209715200 sectors
 Units = sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disk label type: dos
 Disk identifier: 0xddf99f40
 Device Boot
 Start
 End
 Blocks Id System
 Command (m for help): q

I create a partition and format with ext2

[root@Host-164 ~]# mke2fs /dev/sdb1
 mke2fs 1.42.9 (28-Dec-2013)
 Filesystem label=
 OS type: Linux
 Block size=4096 (log=2)
 Fragment size=4096 (log=2)
 Stride=0 blocks, Stripe width=0 blocks
 6553600 inodes, 26214144 blocks
 1310707 blocks (5.00%) reserved for the super user
 First data block=0
 Maximum filesystem blocks=4294967296
 800 block groups
 32768 blocks per group, 32768 fragments per group
 8192 inodes per group
 Superblock backups stored on blocks:
 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
 4096000, 7962624, 11239424, 20480000, 23887872
 Allocating group tables: done
 Writing inode tables: done
 Writing superblocks and filesystem accounting information: done

I mount:

[root@Host-164 ~]# mount /dev/sdb1 /mnt/vol1

I fill the volume from the client, and it works. I check the activity in the Server with iostat and there are more MB/s written to the Server’s drives than actually speed copying in the client.

I completely fill 100GB but speed is slow. We are working on a 10Gbps Network so I expected more speed.

I check the connections to the Server:

[root@obs4602-1810 ~]# netstat | grep -v "unix"Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State      
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55300        ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55298        ESTABLISHED
tcp        0      0 xxx.yyy.18.10:ssh            xxx.yyy.12.154:57137         ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55304        ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55301        ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55306        ESTABLISHED
tcp        0      0 xxx.yyy.18.10:ssh            xxx.yyy.12.154:56395         ESTABLISHED
tcp        0      0 xxx.yyy.18.10:ssh            xxx.yyy.14.52:57330          ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55296        ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55305        ESTABLISHED
tcp        0      0 xxx.yyy.18.10:ssh            xxx.yyy.12.154:57133         ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55303        ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55299        ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.176:57542        ESTABLISHED
tcp        0      0 192.168.10.10:iscsi-target  192.168.10.180:55302        ESTABLISHED

I see many connections from Host 180, I check that and another member of the Team is using that client to test with vdbench against the Server.

This explains the slower speed I was getting.

Conclusions

  1. There was a local problem on the Host. The problems with the disconnection seem to be related to a connection that was lost (sdg). All that information was written to iSCSI buffer, not to the Server. In fact, that volume was mapped in the system with another letter, sdg was not in use.
  2. Speed was slow due to another client pushing Data to the Server too
  3. Windows clients with auto reconnect option are not reporting timeout reports while in Red Hat clients iSCSI connection timeouts. It should be increased

Creating a VM for compiling ZFS with RHEL6.10

As you know I created the DRAID project, based in ZFS.

One of our customers wanted a special custom version for their RHEL6.10 installation with a custom Kernel.

This post describes how to compile and install ZFS 7.x for RHEL6.

First create a VM with RHEL6.10. Myself I used Virtual Box on Ubuntu.

If you need to install a Custom Kernel matching the destination Servers, do it.

Download the source code from ZFS for Linux.

install the following packages which are required by zfs compiler:

sudo yum groupinstall "Development Tools"
sudo yum install autoconf automake libtool wget libtirpc-devel rpm-build
sudo yum install zlib-devel libuuid-devel libattr-devel libblkid-devel libselinux-devel libudev-devel
sudo yum install parted lsscsi ksh openssl-devel elfutils-libelf-develsudo yum install kernel-devel-$(uname -r)

steps to compile the code:1- make sure  the zfs file exists under zfs/contrib/initramfs/scripts/local-top/

if not exists, create a file called zfs  under zfs/contrib/initramfs/scripts/local-top/  and add the following to that file:

#!/bin/sh
PREREQ=”mdadm mdrun multipath”

prereqs()
{
       echo “$PREREQ”
}

case $1 in
# get pre-requisites
prereqs)
       prereqs
       exit 0
       ;;
esac


#
# Helper functions
#
message()
{
       if [ -x /bin/plymouth ] && plymouth –ping; then
               plymouth message –text=”$@”
       else
               echo “$@” >&2
       fi
       return 0
}

udev_settle()
{
       # Wait for udev to be ready, see https://launchpad.net/bugs/85640
       if [ -x /sbin/udevadm ]; then
               /sbin/udevadm settle –timeout=30
       elif [ -x /sbin/udevsettle ]; then
               /sbin/udevsettle –timeout=30
       fi
       return 0
}


activate_vg()
{
       # Sanity checks
       if [ ! -x /sbin/lvm ]; then
               [ “$quiet” != “y” ] && message “lvm is not available”
               return 1
       fi

       # Detect and activate available volume groups
       /sbin/lvm vgscan
       /sbin/lvm vgchange -a y –sysinit
       return $?
}

udev_settle
activate_vg

exit 0

make the created zfs file executable:

chmod +x  zfs/contrib/initramfs/scripts/local-top/zfs

2-  inside  draid-zfs-2019-05-09 folder, execute the following commands:execute Auto generate script:

./autogen.sh

execute configuration script:

./configure

Please note we use this specific configuration for bettter results:

./configure –disable-pyzfs –with-spec=redhat

create rpms:

make rpm

remove all test rpms:

rm zfs-test*.rpm

3- install all created rpms

yum install *x86_64* -y

4- verify that zfs is been installed

zfs

this command will display zfs help. 

Another interesting trick I instructed my Team to do is to add a version number to zfs, with a parameter -v or –version.

So if you want to do the same, you have to edit:

zfs/cmd/zfs/zfs_main.c

Under:

cmdname = argv[1];

In my code is line 7926, then add:

/* DRAIDTEAM - added new command to display zfs version*/
if ((strcmp(cmdname, "-v") == 0) || (strcmp(cmdname, "--version") == 0)) {
    (void) fprintf(stdout, "0.7.0_DRAID-1.2.9.08021755\n");
    return (0);
}

You can check the Kernel Module info by using modinfo zfs, but I found it handy to allow to just do:

zfs -v