zip-files from windows in linux - encoding problem

 unzip -O CP852 file.zip

LVM - recovery of a temporarily failed disk/PV, missing PV

https://www.golinuxcloud.com/recover-lvm2-partition-restore-vg-pv-metadata/#Step_2_Restore_PV_Physical_Volume_in_Linux

 

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/4/html/cluster_logical_volume_manager/mdatarecover

https://serverfault.com/questions/788202/locked-lvm-logical-volume-in-vg-with-missing-pv

Similar to Can't remove volume group, solved this problem by creating a temporary pv with the same uuid:

UUID="RQr0HS-17ts-1k6Y-Xnex-IZwi-Y2kM-vCc5mP"  # from question
dd if=/dev/zero of=/tmp/tmp.raw bs=1M count=100 
losetup -f
losetup /dev/loop0 /tmp/tmp.raw
pvcreate --norestorefile -u $UUID /dev/loop0   # it has arisen!
killall lvmetad      # so it stops complaining about duplicate uuids (dulezite)
pvremove /dev/loop0  # a clean removal 
losetup -D
pvscan --cache       # to restart lvmetad

https://serverfault.com/questions/894410/cant-remove-volume-group

You cannot use --removemissing or force delete VG if metadata area equal zero as in my case.

Make block device from file and include in $VG:

dd if=/dev/zero of=/tmp/tmp.raw bs=1M count=100
losetup -f
losetup /dev/loop0 /tmp/tmp.raw
vgextend $VG /dev/loop0

After that I have Metadata Areas 1

vgremove --force $VG

and remove pvdevice:

pvremove /dev/loop0

compression

 https://linuxreviews.org/Comparison_of_Compression_Algorithms

 https://www.privex.io/articles/which-compression-algorithm-tool/

 

 

Summary - which compression algorithms are best for each usecase?

Fastest compression and decompression: LZ4

Highest overall compression ratio: XZ

Compromise between compression ratio and speed: BZIP2 using LBZIP2

Most widely used / compatible compression algorithm: GZIP

 

My test:     256060514304  linux-sda.raw (239G) (almost empty disk image)

program	size	secs.	speed	real	user	sys
pigz	10457259791	382.226 s	27.4 MB/s	6m22.2s	79m49.8s	10m14.8s
pbzip2	10147770833	511.313 s	19.8 MB/s	8m31.3s	151m19.4s	6m25.3s
lbzip2	10135040141	427.531 s	23.7 MB/s	7m7.5s	65m57.9s	3m23.1s
plzip	28286275683	1033.31 s	8.0 MB/s	17m13.3s	529m13.4s	3m1.4s
xz -T0	8183670908	887.644 s	9.2 MB/s	14m47.9s	339m29.3s	2m40.7s

 

My test 2:     10400825344  tmp.qcow2 (9.7G)

program	size	secs.	speed	real	user	sys
pigz	4452123186	24.9386 s	179 MB/s	0m24.9s	8m52.9s	0m30.6s
pbzip2	4230752746	67.2459 s	62.9 MB/s	1m7.3s	33m10.6s	1m5.4s
lbzip2	4228282477	33.8341 s	125 MB/s	0m33.1s	16m43.6s	0m29.0s
plzip	3808851634	155.09 s	24.6 MB/s	2m35.1s	79m57.5s	0m35.6s
xz -T0	3756465944	156.155 s	24.1 MB/s	2m36.4s	79m7.2s	0m30.9s

Intel(R) Xeon(R) CPU E5-2697A v4 @ 2.60GHz, 16core/32threads, 128G ram