Kunakili kiasi kwa mifumo ya uhifadhi kupitia seva ya Linux kwa kutumia XCOPY

Inatokea kwamba unahitaji kupata nakala kamili ya kiasi ndani ya mfumo mmoja wa hifadhi ya data (DSS), si snapshot, clone, lakini kiasi kamili. Lakini mfumo wa uhifadhi hauruhusu kila wakati hii kufanywa ndani kwa kutumia njia zake mwenyewe. Inaonekana kwamba chaguo pekee ni kunakili kupitia seva, lakini katika kesi hii kiasi kizima cha data kitaendeshwa kupitia seva yenyewe, mtandao kwenye mfumo wa hifadhi na bandari za kuhifadhi, kupakia vipengele hivi vyote. Lakini kuna amri za SCSI ambazo zinaweza kukuruhusu kufanya kila kitu ndani ya mfumo wa uhifadhi yenyewe, na ikiwa mfumo wako unaunga mkono VAAI kutoka VMware, basi ni karibu 100% kwamba amri ya XCOPY (EXTENDED COPY) inasaidia, ambayo inaambia safu nini na wapi kunakili, bila kuhusisha seva ya mchakato na mtandao.

Inaonekana kila kitu kinapaswa kuwa rahisi, lakini sikuweza kupata maandishi yaliyotengenezwa tayari mara moja, kwa hivyo ilibidi nirudishe gurudumu. Linux ilichaguliwa kwa mfumo wa uendeshaji wa seva, na amri ya ddpt (http://sg.danny.cz/sg/ddpt.html) ilichaguliwa kama zana ya kunakili. Kwa kutumia mchanganyiko huu, unaweza kunakili kiasi chochote kutoka kwa OS yoyote, kwani kunakili hutokea block-by-block kwenye upande wa mfumo wa hifadhi. Kwa kuwa ni muhimu kunakili kizuizi kwa kuzuia, na idadi ya vitalu lazima ihesabiwe, amri ya blockdev ilitumiwa kuhesabu idadi ya marudio hayo. Saizi ya juu zaidi ya kizuizi ilipatikana kwa majaribio; ddpt haikufanya kazi na kizuizi kikubwa. Matokeo yake yalikuwa maandishi yafuatayo rahisi:

#!/bin/bash
# first parameter = input device
# second parameter = output device
# device size must be the same
# changing bs variable can reduce speed, max speed should be at bs=32768. 32768 is max setting, lower settings should be calculated dividing by 2

set -o nounset
bs=32768
s=`blockdev --getsz $1`
i=0
while [ $i -le $s ]
do
ddpt of=$2 bs=512 oflag=xcopy,direct if=$1 iflag=xcopy,direct count=$bs verbose=-1 skip=$i seek=$i
i=$(( $i+$bs ))
done

Hebu tuangalie kidogo! Kweli, kama ndogo, faili ya 1TB haikuundwa haraka na kukaguliwa na md5sum :)

root@sales-demo-05:/home/vasilyk# blockdev --getsz /dev/mapper/mpathfs
2516582400
root@sales-demo-05:/home/vasilyk# blockdev --getsz /dev/mapper/mpathfr
2516582400
root@sales-demo-05:/home/vasilyk# mount /dev/mapper/mpathfs /xcopy_source/
mount: /xcopy_source: wrong fs type, bad option, bad superblock on /dev/mapper/mpathfs, missing codepage or helper program, or other error.
root@sales-demo-05:/home/vasilyk# mkfs /dev/mapper/mpathfs
mke2fs 1.44.1 (24-Mar-2018)
Discarding device blocks: done
Creating filesystem with 314572800 4k blocks and 78643200 inodes
Filesystem UUID: bed3ea00-c181-4b4e-b52e-d9bb498be756
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000, 214990848

Allocating group tables: done
Writing inode tables: done
Writing superblocks and filesystem accounting information: done

root@sales-demo-05:/home/vasilyk# mount /dev/mapper/mpathfs /xcopy_source/
root@sales-demo-05:/home/vasilyk# ls -l /xcopy_source/
total 16
drwx------ 2 root root 16384 Aug 19 15:35 lost+found
root@sales-demo-05:/home/vasilyk# head -c 1T </dev/urandom > /xcopy_source/1TB_file
root@sales-demo-05:/home/vasilyk# ls -l /xcopy_source/
total 1074791444
-rw-r--r-- 1 root root 1099511627776 Aug 19 17:25 1TB_file
drwx------ 2 root root         16384 Aug 19 15:35 lost+found
root@sales-demo-05:/home/vasilyk# umount /xcopy_source
root@sales-demo-05:/home/vasilyk# mount /dev/mapper/mpathfr /xcopy_dest/
mount: /xcopy_dest: wrong fs type, bad option, bad superblock on /dev/mapper/mpathfr, missing codepage or helper program, or other error.
root@sales-demo-05:/home/vasilyk# cat xcopy.sh
#!/bin/bash
# first parameter = input device
# second parameter = output device
# device size must be the same
# changing bs variable can reduce speed, max speed should be at bs=32768. 32768 is max setting, lower settings should be calculated dividing by 2

bs=32768
s=`blockdev --getsz $1`
i=0
while [ $i -le $s ]
do
ddpt of=$2 bs=512 oflag=xcopy,direct if=$1 iflag=xcopy,direct count=$bs verbose=-1 skip=$i seek=$i
i=$(( $i+$bs ))
done
root@sales-demo-05:/home/vasilyk# time ./xcopy.sh /dev/mapper/mpathfs /dev/mapper/mpathfr
real    11m30.878s
user    2m3.000s
sys     1m11.657s

Nini kilikuwa kikitokea kwenye mfumo wa kuhifadhi wakati huo:

Wacha tuendelee na Linux.

root@sales-demo-05:/home/vasilyk# mount /dev/mapper/mpathfr /xcopy_dest/
root@sales-demo-05:/home/vasilyk# ls -l /xcopy_dest/
total 1074791444
-rw-r--r-- 1 root root 1099511627776 Aug 19 17:25 1TB_file
drwx------ 2 root root         16384 Aug 19 15:35 lost+found
root@sales-demo-05:/home/vasilyk# mount /dev/mapper/mpathfs /xcopy_source/
root@sales-demo-05:/home/vasilyk# md5sum /xcopy_source/1TB_file
53dc6dfdfc89f099c0d5177c652b5764  /xcopy_source/1TB_file
root@sales-demo-05:/home/vasilyk# md5sum /xcopy_dest/1TB_file
53dc6dfdfc89f099c0d5177c652b5764  /xcopy_dest/1TB_file
root@sales-demo-05:/home/vasilyk#

Kila kitu kilifanyika, lakini jaribu na utumie kwa hatari yako mwenyewe! Kama kiasi cha chanzo, ni bora kuchukua snapshots, kwa wanaoanza.

Chanzo: mapenzi.com