hdparm

how to know what is disk uuid for md raid1 and hdparm?

by

ive got md0 (raid 1) array and want to make write cache off on them during system boot (ubuntu 12.04 server). md0: /dev/sda /dev/sdc blkid: /dev/sda: UUID=”3e502de5-696d-f4b4-470e-XXX” TYPE=”linux_raid_member” /dev/sdb1: UUID=”4ba40aae-65e2-416b-8f17-XXX” TYPE=”ext2″ /dev/sdb5: UUID=”LNt5uO-ZFik-eQ0g-BEhP-FDLi-XXX” TYPE=”LVM2_member” /dev/md0: UUID=”a7eb2443-c3be-45e6-a3eb-XXX” TYPE=”ext4″ /dev/mapper/mydev-root: UUID=”b560f808-db97-4a56-bbf1-XXX” TYPE=”ext4″ /dev/sdc: UUID=”3e502de5-696d-f4b4-470e-XXX” TYPE=”linux_raid_member” /dev/mapper/mydev-swap_1: UUID=”49b806fe-95a6-4ddf-9c47-XXX” TYPE=”swap” hdparm -W 0 /dev/sda (or /dev/sdc) works ok, but … Read more

Differences between hdparm –read-sector and dd with “Current Pending Sectors”

by

This was originally an “answer” to How to use hdparm to fix a pending sector? I’d been getting SMART notifications for the same “Current Pending Sector” for days. The dd solutions around weren’t resolving anything (they’d appear to zero data and re-write it but didn’t effect the smart status). Be warned, I am no guru … Read more

Hdparm slow server

by

My web site server is very slow and I contacted my hosting company. This company ask me to execute this command line: hdparm -tT /dev/sda The result is here: /dev/sda: Timing cached reads: 1112 MB in 2.00 seconds = 555.55 MB/sec Timing buffered disk reads: 4 MB in 4.80 seconds = 854.16 kB/sec I don’t … Read more

Is it possible to get hdparm to report the current level of performance degradation on my SSD?

by

I work on a product that is a headless Debian Linux system with removable Intel X-25M solid state drives. Recently we noticed that the read/write performance of these drives degrades over time, and sure enough the culprit was SSD block problems, as described here. So we did a secure erase of the SSD drive (as … Read more

Is wiper.sh working?

by

I’m setting up a server running Ubuntu Precise, and I’m trying to verify if SSD TRIM is working. fstrim is failing: ~ sudo fstrim -v / fstrim: /: FITRIM ioctl failed: Operation not supported So I tried wiper.sh in hdparm: wiper-3.5 sudo ./wiper.sh –verbose –commit /dev/sda1 wiper.sh: Linux SATA SSD TRIM utility, version 3.5, by … Read more

Ubuntu seems to ignore spindown_time in config /etc/hdparm.conf

by

I have /etc/hdparm.conf configured to power down the external USB HDD, but it actually never spins down. When I manually turn it off (hdparm -Y or set its spindown hdparm -S 36) – everything works as expected. It seems like my Ubuntu ignores /etc/hdparm.conf on reboot 🙁 Here’s some useful info: # blkid /dev/sde6: LABEL=”BACKUP-HDD” … Read more

Measuring disk performance for random seeks?

by

I’m setting up a server that involves lots of database writing during regular updates, and I have wildly varying results between different machines. I’m trying to find out what I can expect from different machines (and hosting providers) without having to install the entire software stack to measure performance. I’ve used hdparm -tT on the … Read more

“UNMAP not supported” error on a device that supports UNMAP

by

I was playing with trim/unmap commands on a Samsung SSD (MZ7WD240 model). To check the unmap support on this device i ran the following command: hdparm -I /dev/sda | grep TRIM And as expected the output shows that my device /dev/sda supports trimming: * Data Set Management TRIM supported (limit 8 blocks) * Deterministic read … Read more