From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Furness Subject: How fast should my hard disk go? Date: 17 Jul 2003 12:08:03 +0100 Sender: linux-admin-owner@vger.kernel.org Message-ID: <1058440083.10502.47.camel@Zebra.vil.ite.mee.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-admin@vger.kernel.org Hello. I have been having performance issues on several systems running, variously, RedHat 7.3, RedHat 9, Slackware and Debian. Everythign was jerky and any copying froze the system for ages. Since this is a dual 2600 CPU with 1G of memory, it was obviously not just a slow machine. Further investigation showed that the hard disk was crawling - typically 2.8 MB/sec were being reported by hdparm. I added the line "idebus=66" to the kernel boot params, and this has made a big difference. However, I'm not convinced that it's working as fast as it should. It might be that I don't understand how IDE disk speed is measured, so I'm hoping that someone who does can explain to me exactly what is happening. I have a 133 speed hard disk connected to a 133 controller. I believe that this should mean that I get a maximum transfer rate of 133 MB/sec? The disk has an 8M cache on it, which is also supposed to make it faster. So why am I getting speeds of just under 50MB/sec? Is this correct (because the max transfer is only in one direction or something), or am I missing an obvious setting? hdparm supplied info is below. Will it go faster?! :) Thanks. Paul. Zebra# hdparm -t /dev/hda /dev/hda: Timing buffered disk reads: 64 MB in 1.35 seconds = 47.41 MB/sec Zebra# hdparm /dev/hda /dev/hda: multcount = 16 (on) IO_support = 1 (32-bit) unmaskirq = 1 (on) using_dma = 1 (on) keepsettings = 0 (off) readonly = 0 (off) readahead = 8 (on) geometry = 238216/16/63, sectors = 240121728, start = 0 Zebra# hdparm -I /dev/hda /dev/hda: ATA device, with non-removable media Model Number: Maxtor 6Y120L0 Serial Number: Y40K7V5E Firmware Revision: YAR41VW0 Standards: Supported: 7 6 5 4 Likely used: 7 Configuration: Logical max current cylinders 16383 16383 heads 16 16 sectors/track 63 63 -- CHS current addressable sectors: 16514064 LBA user addressable sectors: 240121728 device size with M = 1024*1024: 117246 MBytes device size with M = 1000*1000: 122942 MBytes (122 GB) Capabilities: LBA, IORDY(can be disabled) Queue depth: 1 Standby timer values: spec'd by Standard, no device specific minimum R/W multiple sector transfer: Max = 16 Current = 16 Advanced power management level: unknown setting (0x0000) Recommended acoustic management value: 192, current value: 254 DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6 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: * NOP cmd * READ BUFFER cmd * WRITE BUFFER cmd * Host Protected Area feature set * Look-ahead * Write cache * Power Management feature set Security Mode feature set * SMART feature set * FLUSH CACHE EXT command * Mandatory FLUSH CACHE command * Device Configuration Overlay feature set * Automatic Acoustic Management feature set SET MAX security extension Advanced Power Management feature set * DOWNLOAD MICROCODE cmd * SMART self-test * SMART error logging Security: Master password revision code = 65534 supported not enabled not locked frozen not expired: security count not supported: enhanced erase HW reset results: CBLID- above Vih Device num = 0 determined by the jumper Checksum: correct