The settings you mentioned are already set this way. After you apply these settings the logs will be written to your SSD instead of being flushed to the disc array. Those are probably the system logs being flushed to disk every few seconds. I have moved the system data to my boot SSDs, don’t have any apps installed and don’t have any pool set for apps.
This will activate the fault LED for element 9 (Slot 08) on the first SES device. You can avoid any uncertainty by enabling the “locate” or “fault” LED for the drive you mean to replace. This example creates a new GPT partition scheme on da36, creates a 4 GiB swap partition aligned to 1 MiB boundaries, and then adds a ZFS partition with the label e3s01-ZGY0XH87 using the remainder of the space on the disk.
Other interfaces for remote storage include iSCSI, Fiber-Channel, Infiniband, RoCE, and others, but those specialized solutions are beyond the scope of this article. Serial Attached SCSI (SAS) is the most common interface for enterprise storage, first appearing in 2004. Serial ATA (SATA) is the familiar interface used for non-enterprise storage, and is an extension of the original ATA interface dating from the 1980s. In this article we will discuss some strategies and tools to make managing disk arrays on FreeBSD (and related platforms like TrueNAS Core) much easier. It may be what you want is to enable HDD standby, which will “spin down” the drives when not in use
For chassis with larger numbers of drives, or when connecting external JBOD chassis, it is common for the drives to connect to a specialized board that provides power and routing for the SATA/SAS signals to the controller. When building a storage system, there are many different ways the disks might be connected to the system. NVME-oF allows storage devices and arrays in remote chassis to be connected to local motherboards. NVMe storage comes in many form factors, from small M.2 devices to U.2 and other hot-swappable formats intended for servers. NVMe connects storage devices directly to the PCIe bus, offering extremely low latency and high throughput.
While I have been aware of this in my home server as well, it is easy to forget to ensure that disks are not silently killing themselves by cycling the heads. With modern, especially Enterprise grade hard drives being able to have hundreds of thousands of head park operations in their service life, is this really an isssue? With the tools presented here, the reader is well armed to react to failed disks and ensure that the wrong disk isn’t accidentally pulled. However, if a disk has died entirely, or a slot is empty, it might not have a device name. Sesutil can also be used to locate the disk in the physical array.While the SES data tells us that there is an 8 TB disk in Slot 06, it does not tell us which slot in the chassis corresponds to 06. Looking at a few items from the output, we can see the device names (/dev/da0 and /dev/da7 respectively) of the disks in Slot00 and Slot07.
At somewhat larger scales, a number of drives can be connected directly to a SAS (or SATA) controller PCIe card. But, if the number of ports on the motherboard is sufficient to your needs, this is the easiest way to connect reveryplay the drives to the system. We are going to focus on some of the most popular for SATA and SAS drives.
Below we will discuss exactly how to do this with FreeBSD’s sesutil or the management tools for your HBA. Though a truism, it bears emphasizing that with a little planning, management and maintenance of storage systems can be made easier and safer. The total throughput possible from the connected disks is still limited by the number of lanes available, but this is likely the best approach in systems with more than a dozen disks.
Most Seagate disks have configurable Extended Power Conditions (EPC) settings that include timers for how long the disk needs to stay idle before entering various low-power modes. Disk vendors typically provide their own vendor-specific ways to do persistent configuration of power management settings, so it’s worth trying to use those instead so the desired configuration doesn’t depend on the host system applying it, instead being configured in the drive (but in some cases it might be desirable to have the host configure that!). To prevent parking the heads at all a value greater than 128 may do the job (254 is a common choice, as the highest-power setting available), but it’s possible that some disks won’t behave this way because the ATA specification refers only to spinning down the disk and does not specify anything about parking heads. Typical SAS connectors support up to 4 drives per “lane”, but with an expander up to 255 devices are possible. An eight lane controller can only directly attach to 8 disks, requiring more controllers (consuming additional PCI-E slots) to connect more drives. This has long been the interface bus used by most home users to connect their hard drives, and is supported by nearly every motherboard.
I will optimize settings later for the security/quietness tradeoff however, I’m very pleased with it for now. How can I set this value on the Truenas interface? Keeping it spinning but not accessing data is safer. I would still recommend against idling your drive as that reduces longevity. I also set the tunable vfs.zfs.txg.timeout to a somewhat large value so the regular syncs don’t happen every 5 seconds.
Unfortunately, APM settings don’t persist between power cycles so if we wanted to change disk settings with APM they would need to be reapplied on every boot. Advanced power management levels80h and higher do not permit the device to spin down to save power. For example, a device may implement one power management method from 80h to A0h and a higherperformance, higher power consumption method from level A1h to FEh. To prevent parking more often that is useful (for a server, usually that choice would be “very rarely”), there are a couple ways to do it and which apply will depend on what the hard drive vendor’s firmware supports. With the SMART metrics captured by Prometheus, it’s fairly easy to write a query that will show how often a given disk is parking its heads. Since I use Prometheus to capture information on the server’s operation however, I can use that to monitor that my hard drives are doing well.
If your system has multipath SAS, each disk will be present more than once, and you should use the gmultipathcommand to deduplicate your disks and for labeling as well. FreeBSD supports a number of different ways to label the disk, depending on your use case. The map command displays all of the SES devices and each element (this is the nomenclature in SES) connected to them. Of course, all of this chassis management technology isn’t very effective without tools to make it usable. It also provides information about each slot in the enclosure (even if empty), including a flag to indicate if the device has recently been swapped.
However, I noticed that my HDD’s heads park (particulary Seagate Exos) every 3 minutes. ZFS is widely trusted for large-scale storage, but production environments expose design mistakes,… When dealing with critical data, you only get one chance to do it right. The status field is a bitmask supporting a number of different options, but the main ones we care about are 1 (OK), and 2 (FAULTED). When combined with a JSON parser like jq, this can be used to automate tasks for each disk.
SAS disk reservations provide the ability to connect to the disk redundantly—or even across multiple machines—while ensuring it is only used by one of them at a time. SAS provides many more features than SATA does—including full duplex operations, advanced error recovery, multipath, and disk reservations. It too was an extension on an existing interface bus which offered greatly improved performance. SATA+AHCI improved data transfer speeds, simplicity of communication, and included abilities that we today take for granted, such as “hot swap” and command queueing. These concepts also apply to other operating systems, but the tools might differ slightly.
FreeBSD’s sesutil is a tool to interface with the SES devices on your system. You should also configure smartd to monitor your disks and send you alerts, which may give you advanced notice when a drive is starting to fail. These special boards, called SAS Expanders, reduce the total cabling required to provide power and signal pathways to all connected disks.
It is fairly well-known among techies that hard drives used in server-like workloads can suffer from poor configuration by default such that they frequently load and unload their heads, which can cause disks to fail much faster than they otherwise would. My Seagate Archive SMR disk (which began life as an external hard drive and was retired from that role when it became too small to hold as much as I wanted to back up to it) apparently doesn’t support reporting EPC settings (since asking for them says so), and initially didn’t accept new values for the idle timers either. The Prometheus Node Exporter is the canonical tool for capturing machine metrics like utilization and hardware information with Prometheus, but it alone does not support probing SMART data from storage drives. While SSDs don’t have any heads to park, most do report a media_wearout_indicator that represents the amount of data written to the device in relation to the amount that it’s specified to accept before the Flash storage medium wears out.
I moved the system dataset to the boot pool. I don’t move any data, no apps are running, this is a vanilla Scale install so far, yet the HDD is in constant work. 1 SSD to boot and 1 HDD to store data. Agree, I have used SeaChest with good results for this same issue on scale plus drive cache. If you do it on a live pool, I’d back up your data first.
When it comes to long-term data storage, there are several strategies and media types that Redditors recommend. It refreshes the disks SMART information every 5 min. ZFS and Btrfs both aim to modernize storage by combining filesystems and volume management, but… Monitoring and maintaining your storage media is one of the most important parts of keeping your data safe.
