Tech Articles

Disk Details


Tech Articles ID    KB8022070
Status:    Published
Published date:    04/23/2015
Updated:    06/29/2015
Reported In:   MSC Nastran
 

Abstract (Question)

Summary

  •     SSD disks are very fast and highly recommended for scratch space.
  •     Disk speeds range from 7000 RPM to 15000 RPM. Faster disks may help performance.
  •     Using RAID0 with multiple disks is recommeneded.

Description (Answer)

Below is a comparison between SCSI and SSD disks for a few models on a HASWELL system. 

Commands

HDPARM can be used on Linux systems for a mild comparison of disk speed. Below are examples from an SSD disk and a SCSI disk. The SSD disk is listed at 480 Mb/sec while the SCSI is listed at 123 Mb/sec. There are other tools, but "hdparm" gives a quick summary:

    [Node]# hdparm -t /dev/sda1
    /dev/sda1:
     Timing buffered disk reads: 1442 MB in  3.00 seconds = 480.08 MB/sec

    [Node]# hdparm -t /dev/sdb1
    /dev/sdb1:
     Timing buffered disk reads: 372 MB in  3.02 seconds = 123.31 MB/sec

DISK TYPE may be determined by looking at /proc/scsi/scsi

    [Node]# cat /proc/scsi/scsi
    Attached devices:

    Host: scsi0 Channel: 00 Id: 00 Lun: 00
      Vendor: ATA      Model: SSD2SC240G3LC726 Rev: 524A
      Type:   Direct-Access                    ANSI  SCSI revision: 05
    Host: scsi1 Channel: 00 Id: 00 Lun: 00
      Vendor: ATA      Model: WDC WD1002FAEX-0 Rev: 05.0
      Type:   Direct-Access                    ANSI  SCSI revision: 05

Creating a Raid device may be done with mdadm:

     mdadm --create --verbose /dev/md0 --level=raid0 --raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1

Caveats

  •     Disk speeds may vary
  •     Some SSD disks may not be as reliable as others.

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