Tom Goldberg
Forum Replies Created
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As the Cache-A guy on the Cow, I would like to jump in here and try to address a number of the issues being mentioned in this thread.
First, the CatDV plugin does not deal with spanned tapes aka Multiple Volumes. As you add tapes to a spanned set on a Cache-A, we automatically rename each subsequent tape with the volume name of the first tape in the set (i.e. “myfiles) followed by an underscore tape number (i.e. myfiles_2, myfiles_3). The CatDV plugin does not recognize this policy at this time.
The CatDV plugin does display the % space left on tape upon invoking an archive. This allows you to manage your archive transfers to fit on tapes. In general, spanned sets are to be avoided if possible – they’re ok for archiving large data sets that need to remain intact, but not needed for CatDV managed files.
In order to restore files with CatDV’s plugin, they must already have been restored to the VTAPE by the user first. CatDV is actively working on being able to restore directly from tapes, but they will have to comment on the availability of that feature for what version of their plugin.
Lindsay, the kind of media you are archiving is irrelevant, we are a data device and when it comes to archiving, bits are bits. Because you are getting file transfer errors, I’d suspect your network, your physical connections, your archive source hard drives, your PC configuration… something in your system. Because we have a lot of units deployed, and problems like yours are most likely to be due to such end-user system issues.
Nathan, have you contacted our tech support? We can help you through some of these issues. Are you trying to use LTFS (not tested with the CatDV plugin)? What version is your Cache-A (you should be at v2.1.15)? Is it under warranty (Lindsay’s is not)?
Jeff, you seem to be on the right path. I hope some of these explanations help explain issues you’ve had.
I hope all of you can work through your issues and will be here to address this kind of topic… usually over on the Archiving and Backup forum, but happy to contribute here as well.
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
Yes, tapes can be freely erased and reused.
It may be instructive to view the “Tape Information” dialog – if you see a lot of “Space Lost,” this may be indicative of many bad blocks and suggests that you may not be able to get a full amount of data on the tape the next time you use it. On the other hand, there can also be space lost due to issues with data delivery as appears may be the case in your logs.
Also, we suggest not reusing tapes that have a large number of Loads (i.e. over 200) as there is a possibility they might be getting worn in some areas.
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
Hi Lindsay,
The error dialog you got from your Cache-A device “TOC position invalid” tells us that there is no Table of Contents (TOC) file where we recorded it last being written. The TOC location is stored in the cartridge memory chip and is updated upon each session completion.
The only time this error happens is when an archive session is not completed – this may have been due to a power interruption or a system crash during an archive.
While it may be possible for our support engineers to repair such a tape, the easiest way to fix this is to recover all and re-archive it.
I hope this helps!
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
Hi Lindsay,
The error dialog you got from your Cache-A device “TOC position invalid” tells us that there is no Table of Contents (TOC) file where we recorded it last being written. The TOC location is stored in the cartridge memory chip and is updated upon each session completion.
The only time this error happens is when an archive session is not completed – this may have been due to a power interruption or a system crash during an archive.
While it may be possible for our support engineers to repair such a tape, the easiest way to fix this is to recover all and re-archive it.
I hope this helps!
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
Hi David,
Unfortunately we are still a ways off from fixing this problem with Lion. It turns out that to fix this, we need to replace a good portion of the Linux utilities we use to connect with Macs. This upgrade will take significant effort and affects many moving parts in our software… we recognize the problem and know it will be much easier for our customers once it is fixed, but I’m sorry I can’t promise it to you soon enough to address any immediate issues.
What I can do is offer the support to walk you through the process. You don’t need to be fluent to use terminal, just careful and follow instructions.
Terminal can be your friend – it is a cool tool once you get to know a few things… in preparation for us helping you, take a look through our simple tech brief: Command Line Access to Cache-A Appliances
Once you’ve had a look, give our support group a call and we’ll make sure you get connected.
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
Hi Lindsay,
I see that you have sent this same message to our support group – we will help you drill down into the details of your issues via our normal support processes. Please email those logs to support@cache-a.com.
For the benefit of the Cow community, however, I would like to note that any errors that appear in an archive session log indicates issues that should not be ignored. Whether content compresses or not never appears in the logs and is completely transparent to the archiving process except how much space on tape any given content consumes.
When you see an archive error you should never assume the session successfully archived all your data. Such issues may be due to network problems, source hard disk drive issues, bad data or file system errors in the source material, or potentially a hardware issue with the Cache-A itself. The time to catch and address any errors is at archive time. Finding out when you try to restore it is too late.
Cache-A support stands ready to help all in-warranty customers whenever they encounter archiving problems – don’t hesitate to contact us.
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
Hi Jack,
Normally I keep and eye on the Archiving and Backup forum but am happy to jump over here.
We appreciate Fred’s interest in helping, but as we are the manufacturer of your subject query, I’d like to provide some further explanation.
As you noted, with our gear, you store your content to tape over a network – our systems offer a share (just like on any NAS) and whatever you copy to this share can be either automatically or manually moved to LTO tape at high speed. We don’t care whether that content is rushes or camera raw – we store everything on tape by filename and allow you to tag additional metadata to any file, folder or tape. There is plenty more information about and lists of video outfits currently using our solutions on our web site at cache-a.com. You may want to contact one of our dealers listed on the site – they can explain more and many can provide demos.
Just to correct a few points, our systems are “appliances” that connect simply and require no software on your workstations. They are in fact self-contained Linux servers that today are running on core2duo processors (not xeons) but all of this is transparent to the user. Also, all versions of LTO tapes contain a small memory chip that tracks usage and manufacturer’s data but user data all goes onto tape.
I hope this has helped explain our approach but feel free to email me or post further if you have more questions.
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
Gary’s plan is exactly our easiest recommended workflow for Avid environments.
Many of our customers just normally create a workspace per project and don’t even have to consolidate – just archive the workspace when the project is complete (or at various points along the way as needed). The only caution we’d have is to either make sure your content will fit on one tape (~1425GB for LTO-5) or span tapes but make sure you have enough blank tapes for the full archive before starting.
If your Avid shared storage offers up a LAN share, you can mount that directly on the Cache-A and bypass your workstation. If it does not, you will have to go through a Unity client (Mac or PC) to get the content over your network to the Cache-A.
If you are having problems with any of this, Cache-A support will be happy to help.
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
To explain further about the issue Bob brings up, this is not just a Cache-A problem.
With Mac OS 10.7 Lion, Apple has decided in its infinite wisdom to disable some older methods for authenticating users in the name of security. One of these “UAM’s” or “User Authentication Modules” that was disabled is DHCAST128 – the one used by every Linux system that shares volumes to Macs.
Apple provides instructions for re-enabling this as Bob has quoted above, but it does require a trip to terminal land and having a spare Mac around with a share that will mount. This only has to be done once to each Lion system, but certainly is inconvenient. I would maintain that this old authentication method has never been a security hole and Apple’s unilateral and sudden change was a bad decision.
No doubt, the Linux open-source community will respond and new afp authentication will come along in due time – as soon as this becomes available, we will add it to our products, but in the mean time, this tech brief is the only solution.
We’ve had a number of customers use it successfully but would certainly be interesting in hearing if others have shared Bob’s difficulties.
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com -
The only way I know of to find out if you NEED this info is to run a test, omitting it on a sample project and see if your applications have any trouble with the restored data.
This info is not useful for LTFS listings because it takes so long to pull off tape for each file – this is why we recommend only using a List view when looking at the actual LTFS volume.
Someday we will have a way to hide all those AppleDouble files, but I feel your pain having to see them in file lists today!
Tom Goldberg
Cache-A Corporation
602 Park Point Drive
Golden, CO 80401
mailto:tom.goldberg@cache-a.com
https://cache-a.com