What is the best way to Over-provision SSD using Partitions


#1

we use Intel S3500 480G SSD , in the aerospike doc http://www.aerospike.com/docs/operations/plan/ssd/ssd_setup.html , is not 4K align, i want to know is it diffrent it these two way ?

fdisk /dev/sdc

$ fdisk /dev/sdc
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-19140, default 1): 1
Last cylinder, +cylinders or +size{K,M,G} (1-19140, default 19140): 15121

Command (m for help): p
Disk /dev/sdb: 157.4 GB, 157437394944 bytes
255 heads, 63 sectors/track, 19140 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xeff8f3ae
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       15121   121459401   83  Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.

fdisk -H 32 -S 32 /dev/sdc

$ fdisk -H 32 -S 32 /dev/sdc

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-914688, default 1): 2
Last cylinder, +cylinders or +size{K,M,G} (2-914688, default 914688): 722600

Command (m for help): p

Disk /dev/sdc: 479.6 GB, 479559942144 bytes
32 heads, 32 sectors/track, 914688 cylinders
Units = cylinders of 1024 * 512 = 524288 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0005a2a8

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               2      722600   369970688   83  Linux

in these two way, which has the best Performance ? or just the same?


Asrestore problem: put failed in restore: unusual error 18 trying again
#2

Thanks for your post. Following up and will get back to you.


#3

We do not believe there should be a difference in the two methods, but have not done extensive testing in this. While these may make a difference in rotational drives, there shouldn’t be much (if any) impact on solid state drives. We will try to test this out for ourselves, but if you find anything confirming or refuting any performance benefit, please let us know.

In some cases, we have seen differences depending on the manufacturer due most likely to the firmware. For example, Intel drives will make use of unpartitioned space for over-provisioning, but some from other manufacturers will not. This may vary depending on the exact version of the firmware as well.

Testing is the only way to be certain of the impact.