On 1/29/2015 4:50 AM, Gordon Messmer wrote:
On 01/28/2015 04:32 AM, Jatin Davey wrote:
Could someone point me on how to improve the disk I/O on my server and reduce the wait time on I/O.
Start by identifying your disk and controller. Assuming that this is a single SATA disk:
# smartctl -a /dev/sda | egrep 'Model:|Rate:|SATA Version'
[Jatin] [root@localhost images]# smartctl -a /dev/sda | egrep 'Model:|Rate:|SATA Version' [root@localhost images]#
# lspci | grep SATA
[Jatin] [root@localhost images]# lspci | grep SATA 00:11.4 SATA controller: Intel Corporation Wellsburg sSATA Controller [AHCI mode] (rev 05) 00:1f.2 SATA controller: Intel Corporation Wellsburg 6-Port SATA Controller [AHCI mode] (rev 05)
Next install and run iotop. If there's something on your system that's particularly active and unnecessary, disable it.
If everything contending for your disk *is* necessary, then you may need to take steps to improve disk performance. There are a number of possibilities.
1: Use an SSD instead of a disk.
2: Use an SSD in addition to a disk. If a purely SSD storage system is too expensive, you might choose to use an SSD for one or more filesytems that you can mount where the high volume IO is occurring, and continue to use the disk for filesystems that need more data capacity and fewer IOPS.
[Jatin] Thanks for these inputs. I will surely take it up with my team to see if we can incorporate new hardware for our product.
3: Use a fast RAID array. A RAID1 array can provide better read performance than a single disk. For higher write volumes, use RAID10 on four or more disks. Avoid RAID 5 or 6, as they'll be slower than a single disk.
[Jatin] We are using RAID 10 in our server with 4 disks.
4: Replace poorly supported hardware. It might be that your SATA controller isn't well supported, and performs badly as a result. I used to have a desktop system with NVidia motherboard chipset. Its SATA controller was garbage. Performance with the same disk was noticeably better with a cheap PCI-E SATA controller.
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Hi Gordon
Please see my responses inline to your questions. Appreciate your inputs in this direction.
Thanks Jatin