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I need to prepare the file system of an SSD disk in a way that a Database Administrator pointed me to, which would be a way optimized SSD to work.

I have a disk: SSD: Samsung 500 GB SATA III 6Gb/s - Model: 850 Evo http://www.samsung.com/semiconductor/minisite/ssd/product/consumer/850evo/ http://downloadcenter.samsung.com/content/UM/201711/20171115104118871/Samsung_SSD_850_EVO_Data_Sheet_Rev_3_1.pdf

The DBA said that should be partition aligned to 3072 not default 2048, to start on erase block bounduary. And fs block should be 8kb.

Anyone know if this is even indicated ? Another question, can you give me a hint of what program I could do this. I have already used fdisk but I do not know how to do this in Fdisk. I used Linux Debian 8(Jessie) 64b with Ext4 File system.

Best Regards Neto

  • 2
    3 kB erase block boundary? On a disk that appears to have a 4 kB block size? How could that possibly work? – Andrew Henle Jan 16 '18 at 17:34
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Searching I checked that In past, proper alignment required manual calculation and intervention when partitioning. Many of the common partition tools now handle partition alignment automatically.

For example, on an already partitioned disk, you can use parted ( https://wiki.archlinux.org/index.php/GNU_Parted#Check_alignment ) to verify the alignment of a partition on a device in LInux S.O. This example I ran on my Samsung SSD 500GB 850 Evo, see below:

-------BEGIN PARTED TOOL -------------------------------------------------------------

root@hp2ml110deb:parted /dev/sdb
(parted) print list                                                      
Model: ATA Samsung SSD 850 (scsi)
Disk /dev/sdb: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number  Start  End    Size   File system  Flags
 1      0.00B  500GB  500GB  ext4

Model: ATA MB1000GCWCV (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system     Name  Flags
 1      1049kB  538MB   537MB   fat32                 boot, esp
 2      538MB   992GB   991GB   ext4
 3      992GB   1000GB  8319MB  linux-swap(v1)

(parted) select /dev/sdb
Using /dev/sdb
(parted) align-check
alignment type(min/opt)  [optimal]/minimal? opt                          
Partition number? 1                                                      
1 aligned
(parted)      

---------------------------- END --------------------------------------------------

One question that I have doubts is, if these tools really do align properly, how accurate are they?

  • this doesn't really seem to be an answer. it probably belongs in your question. – cas Jan 17 '18 at 3:57
  • Why no? read this that I write in reply: " I checked that In past, proper alignment required manual calculation and intervention when partitioning. Many of the common partition tools now handle partition alignment automatically." – Neto Jan 18 '18 at 2:26

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