A good, but not infallible, way of checking any drive health is to check the SMART attributes. Below is the SMART attribute set for an Intel X25-M G2 160GB disk, taken using smartctl v5.41. (The version is important, earlier versions of smartctl had different attribute-name mappings, and didn’t actually correctly understand the specific table for … Read more
All drives fail. Either through wear, or though manufacturing fault. By placing those drives in a RAID0 configuration you have doubled the chances of a drive fault destroying your data.
So, some research has been done on this. According to SSD researchers Michael Wei, Laura M. Grupp, Frederick E. Spada, and Steven Swanson, who presented the paper, “Reliably Erasing Data from Flash-Based Drives” (PDF warning), quote: …our results lead to three conclusions: First, built-in commands are effective, but manufacturers sometimes implement them incorrectly. Second, overwriting … Read more
Well, ZFS uses a storage layering called Hybrid Storage Pool (HSP): Layer: memory Layer: SSD-based read-caches (L2ARC) and write-caches (separate intent log aka slog). Layer: (cheap) harddisks With HSP its easy to automatically benefit from the advantages of SSDs compared to a harddisk-only solution. A system using HSP can be both faster and cheaper than … Read more
Cheap SSDs seem to have serious quality issues. You will find lots of users that have issues with your particular drive. However I think that the vendors also sell different drives (e.g. with other NAND chips/controllers) under the same label. So each drive may behave differently. The SMART values give no indication that the drive … Read more
That’s the official answer from OWS, now another answer if it is possible to force hp controller to up it to x2 width, that will require some more research. -)
Yes, I also checked out all on-disk layout of MBR/PBR/GPT/MD/LVM, and came to the same conclusion. For your case (LVM on raw disk), if LVM-PE(physical extent) is 1MB-aligned with pvcreate, you can be sure all futher data allocation will be aligned, as long as you keep allocation size to (1MB * N). Since both “vgcreate … Read more
Sure, you can do this. You can tell ESXi that a particular datastore is comprised of SSDs. Here’s how:Enabling the SSD option on SSD based disks/LUNs that are not detected as SSD by default (2013188) You end up having to set a datastore claim rule similar to: esxcli storage nmp satp rule add –satp SATP_TYPE … Read more
This values are hold in S.M.A.R.T attributes. You cat use smartctl command from smartmontools to get them. UPD smartctl -A /dev/sda | grep -i ‘media_wearout_indicator’ | tr -s ‘ ‘ | cut -d’ ‘ -f4-5 will output VALUE,WORST and THRESHOLD for Media_Wearout_Indicator. Note: for your device the attribute may have different name and threshold value, … Read more
Okay. This is an interesting question, as there are a number of options available to you. Some concepts to clarify and understand, as they relate to this situation: Perceptions of “speed” or “fast”. RAID controller performance. SAS topology. Benchmarking a system and/or identifying bottlenecks. In order to get the maximum performance, we really need each … Read more