I've recently obtained a Samsung EVO 840 1TB SSD as a hard disk replacement for my laptop (Lenovo X220t, core-i5-2520m, 8GB RAM). So far, I'm not impressed with the resulting performance and request some hints on what to try.
I've formatted the drive to have a 1GB boot partition and another partition taking the rest.
Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 96 heads, 32 sectors/track, 635913 cylinders, total 1953525168 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 identifier: 0xf3e3717f Device Boot Start End Blocks Id System /dev/sda1 3072 2101247 1049088 83 Linux /dev/sda2 2101248 1953524735 975711744 83 Linux
The second disk is encrypted using luks and aes-xts-plain64.
> cryptsetup status cryptoroot /dev/mapper/cryptoroot is active and is in use. type: LUKS1 cipher: aes-xts-plain64 keysize: 512 bits device: /dev/sda2 offset: 6144 sectors size: 1951417344 sectors mode: read/write flags: discards
On top of that, there is LVM with the logical partitions.
> vgs VG #PV #LV #SN Attr VSize VFree ssd 1 6 0 wz--n- 930.50g 639.00g > pvs PV VG Fmt Attr PSize PFree /dev/dm-0 ssd lvm2 a-- 930.50g 639.00g > lvs LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert home ssd -wi-ao--- 250.00g root ssd -wi-ao--- 2.50g swap ssd -wi-ao--- 10.00g tmp ssd -wi-ao--- 4.50g usr ssd -wi-ao--- 20.00g var ssd -wi-ao--- 4.50g
AES-NI is active and "cryptsetup benchmark" delivers 900-1000MB/s for aes-xts-512 in both directions.
The system is not a fresh install but the old system was migrated using "cp -a", so there was no image-copy of the old filesystems. Now everything does feel a little faster but so far I'm not impressed. Opening iceweasel still takes 4-5 seconds, pycharm with a relatively small project requires about 20 seconds to startup.
I was running bonnie++ to see the raw performance on the filesystem itself with the following results:
Version 1.97 ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP laptop 16000M 511 99 464061 50 212554 20 3191 99 646813 20 +++++ +++ Latency 39861us 688ms 647ms 3317us 2593us 2161us ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP laptop 128 81349 87 +++++ +++ 71014 63 83195 85 +++++ +++ 59378 56 Latency 81014us 505us 111ms 79458us 14us 114ms
The values for block-wise read and writes look great with 450MB/s and 650MB/s. However, per-character seem really slow with just 0,5MB/s and 3MB/s.
However, I lack a reference to really judge these values. I've seen other machines with a SSD where opening a browser basically happened instantly, similar thing with eclipse of pycharm and I'm wondering why my system does not 'fly' like this. Did I accidentially introduce a huge performance hog somewhere? Or are the numbers fine and my problem lies elsewhere?