[ale] Disk performance

[Alex Carver]

# hdparm -Tt /dev/sda

/dev/sda:
  Timing cached reads:   330 MB in  2.00 seconds = 164.89 MB/sec
  Timing buffered disk reads:  38 MB in  3.13 seconds =  12.16 MB/sec

But I think I found the culprit, the CD drive blew up.  I almost never 
use it (last time I used it was for the installation three years ago).
I rebooted once after I sent the initial email to see what POST said and 
it never announced the CD drive -- it's IDE but it was on the secondary 
channel.  So I shut back down and yanked it off the bus.  Left 
everything else as it was with the exception of removing the suspend 
feature from the kernel (kept hanging for 20-30 seconds running 
libgcrypt at boot to uncompress a non-existent suspend file).

I'm going to give it a few hours and see if it behaves or goes back to 
the lagging.  I'll also be watching the free RAM very closely.  Prior to 
the shutdown it was running with about 20MB free and now it's up at 
390MB free (total system 512MB).



On 8/24/2013 16:00, Calvin Harrigan wrote:
> Try hdparm -Tt /dev/sda and see what you get . It does a read transfer test.
> On Aug 24, 2013 5:39 PM, "Alex Carver" <agcarver+ale at acarver.net> wrote:
>
>> I started revisiting some of the performance issues with one of my systems
>> (slow startup of any program) and removing anything that may have
>> interfered (HAL, fuse, etc., removing atime) so now I'm down to basic disk
>> access.  Using iotop, it seems the disk is running slower than I recall
>> (transfer rates of about 200 K/s).
>>
>> I'd appreciate any suggestions on areas to look short of a wipe and reload
>> (I don't currently have spare drives) but any other performance checks and
>> tweaks would be good.  It had been working fine for a long time and only
>> recently has had any issues.
>>
>> I do have hdparm installed and there are two disks in the system both on
>> the primary IDE channel.
>>
>> The report from hdparm:
>>
>> /dev/sda:
>>
>>   Model=Maxtor 90840D6, FwRev=WAS8283C, SerialNo=K60A721A
>>   Config={ Fixed }
>>   RawCHS=16276/16/63, TrkSize=0, SectSize=0, ECCbytes=29
>>   BuffType=DualPortCache, BuffSize=256kB, MaxMultSect=16, MultSect=16
>>   CurCHS=16276/16/63, CurSects=16406208, LBA=yes, LBAsects=16406208
>>   IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
>>   PIO modes:  pio0 pio1 pio2 pio3 pio4
>>   DMA modes:  mdma0 mdma1 mdma2
>>   UDMA modes: udma0 udma1 *udma2
>>   AdvancedPM=no WriteCache=enabled
>>   Drive conforms to: ATA/ATAPI-4 T13 1153D revision 17:  ATA/ATAPI-1,2,3,4
>>
>> ATA device, with non-removable media
>>          Model Number:       Maxtor 90840D6
>>          Serial Number:      K60A721A
>>          Firmware Revision:  WAS8283C
>> Standards:
>>          Used: ATA/ATAPI-4 T13 1153D revision 17
>>          Supported: 4 3 2
>> Configuration:
>>          Logical         max     current
>>          cylinders       16276   16276
>>          heads           16      16
>>          sectors/track   63      63
>>          --
>>          CHS current addressable sectors:   16406208
>>          LBA    user addressable sectors:   16406208
>>          Logical/Physical Sector size:           512 bytes
>>          device size with M = 1024*1024:        8010 MBytes
>>          device size with M = 1000*1000:        8399 MBytes (8 GB)
>>          cache/buffer size  = 256 KBytes (type=DualPortCache)
>> Capabilities:
>>          LBA, IORDY(can be disabled)
>>          bytes avail on r/w long: 29
>>          Standby timer values: spec'd by Standard
>>          R/W multiple sector transfer: Max = 16  Current = 16
>>          DMA: mdma0 mdma1 mdma2 udma0 udma1 *udma2
>>               Cycle time: min=120ns recommended=120ns
>>          PIO: pio0 pio1 pio2 pio3 pio4
>>               Cycle time: no flow control=120ns  IORDY flow control=120ns
>> Commands/features:
>>          Enabled Supported:
>>             *    SMART feature set
>>             *    Power Management feature set
>>             *    Write cache
>>             *    Look-ahead
>>             *    Host Protected Area feature set
>>             *    WRITE_VERIFY command
>>             *    WRITE_BUFFER command
>>             *    READ_BUFFER command
>>             *    NOP cmd
>>             *    DOWNLOAD_MICROCODE
>>
>>
>>   * signifies the current active mode
>>
>>   multcount     = 16 (on)
>>   IO_support    =  0 (default)
>>   readonly      =  0 (off)
>>   readahead     = 256 (on)
>>   geometry      = 1021/255/63, sectors = 16406208, start = 0
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